Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260330
Tag: weekly-20260330-5fa5ea4e
Previous Weekly Tag: weekly-20260323-98de0277

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260330
# or
uv pip install altair==6.1.0.dev20260330

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260330) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260330-5fa5ea4e
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260330-5fa5ea4e

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260330-5fa5ea4e",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260330-5fa5ea4e" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260330-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260323
Tag: weekly-20260323-98de0277
Previous Weekly Tag: weekly-20260316-49e745b8

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260323
# or
uv pip install altair==6.1.0.dev20260323

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260323) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260323-98de0277
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260323-98de0277

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260323-98de0277",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260323-98de0277" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260323-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260316
Tag: weekly-20260316-49e745b8
Previous Weekly Tag: weekly-20260309-356c78bb

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260316
# or
uv pip install altair==6.1.0.dev20260316

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260316) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260316-49e745b8
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260316-49e745b8

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260316-49e745b8",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260316-49e745b8" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260316-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260309
Tag: weekly-20260309-356c78bb
Previous Weekly Tag: weekly-20260223-903e68e1

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260309
# or
uv pip install altair==6.1.0.dev20260309

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260309) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260309-356c78bb
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260309-356c78bb

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260309-356c78bb",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260309-356c78bb" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260309-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260223
Tag: weekly-20260223-903e68e1
Previous Weekly Tag: weekly-20260216-e85e1e3b

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260223
# or
uv pip install altair==6.1.0.dev20260223

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260223) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260223-903e68e1
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260223-903e68e1

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260223-903e68e1",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260223-903e68e1" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260223-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260216
Tag: weekly-20260216-e85e1e3b
Previous Weekly Tag: weekly-20260126-64e0d685

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260216
# or
uv pip install altair==6.1.0.dev20260216

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260216) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260216-e85e1e3b
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260216-e85e1e3b

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260216-e85e1e3b",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260216-e85e1e3b" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260216-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Weekly Pre-Release Build of Altair

This is a pre-release version for testing purposes.

Build Information

Version: 6.1.0.dev20260126
Tag: weekly-20260126-64e0d685
Previous Weekly Tag: weekly-20260119-a2afad36

Installation

From PyPI (recommended)

Install the latest weekly build directly from PyPI:

pip install altair==6.1.0.dev20260126
# or
uv pip install altair==6.1.0.dev20260126

Note: Weekly builds publish timestamped development versions (for example 6.1.0.dev20260126) to PyPI. When you pin that exact version, pip installs the dev build automatically, without the need for a --pre flag.

From GitHub Repository (direct install)

Install directly from the tagged commit without downloading the wheel:

Command line (pip or uv):

pip install git+https://github.com/vega/altair.git@weekly-20260126-64e0d685
# or
uv pip install git+https://github.com/vega/altair.git@weekly-20260126-64e0d685

Note: Installing directly from the weekly-... tag will surface the base development version (without the timestamp suffix) because the version file edits are not committed.

Add to pyproject.toml (pip/uv):

[project]
dependencies = [
    "altair @ git+https://github.com/vega/altair.git@weekly-20260126-64e0d685",
]

Add to pixi.toml (pixi):

[pypi-dependencies]
altair = { git = "https://github.com/vega/altair.git", rev = "weekly-20260126-64e0d685" }

From GitHub Release (manual download)

Download the wheel file from the assets below and install:

pip install altair-6.1.0.dev20260126-py3-none-any.whl

Testing & Feedback

Please note: This is a testing version. If you encounter any issues or unexpected behavior, we would greatly appreciate if you open an issue to report it. Your feedback helps improve Altair!

Release v6.0.0

The Vega-Altair team is pleased to announce the release of version 6.0.0. Firstly, we are grateful for the many returning contributors (@franzhaas, @dangotbanned, @dsmedia, @joelostblom, @tempdata73, @mattijn, @jonmmease, @eitanlees, @kurtmckee, @MarcoGorelli), and a special shoutout to all the new contributors (@JasonnnW3000, @edmundmiller, @jannisko, @stanmart, @star1327p, @baldwint, @daizutabi, @azjps, @joaopalmeiro, @bobot). You are all awesome!

In short what is included with the version 6 release of Altair.

• we now compile against Vega-Lite version 6 (to be specific, version 6.1.0) and provide support for Python 3.14.
• we have a new datasets module, altair.datasets, lazily access to datasets from https://github.com/vega/vega-datasets.
• we are now thread-safe, altair specifications should be stable after re-running.
• we improved docs and included new examples, eg. this faceted choropleth of habitat species across geographical counties https://altair-viz.github.io/gallery/maps_faceted_species.html.
• we improved the typing experiences.
• we migrated to uv as part of the infrastructure modernization and now have automated weekly builds.

We test all changes thoroughly, but nevertheless, if you encounter any issue or like to start a discussion. Please feel free!

Full details are available in the complete changelog below.

Breaking

• feat: Bump vega-lite>=6 by @franzhaas in #3831

Enhancements

• feat: Show python types in ValidationError messages by @dangotbanned in #3735
• feat: Update vega-lite to 5.21.0 by @dangotbanned in #3761
• feat: Show user_rows in MaxRowsError message by @dangotbanned in #3768
• feat: Allow numpy scalars in altair expressions by @stanmart in #3827
• feat: adds altair.datasets by @mattijn in #3848
• feat: preserve the empty property for the three operators (&, |, ~) by @mattijn in #3853
• feat: hashing of parameter and view names by @mattijn in #3851
• feat: Allow opening the editor without validating the spec by @joelostblom in #3869
• feat: require minimal vegafusion 2 and revert #3857 by @mattijn in #3885
• feat: add warning for deduplications by @mattijn in #3902

Bug Fixes

• fix(typing): Resolve LSP violation for ChartType.data by @dangotbanned in #3740
• fix: Replace circular import in schemapi.py by @dangotbanned in #3751
• fix: Include *(Datum|Value) in SchemaValidationError by @dangotbanned in #3750
• fix: Resolve multiple sphinx warnings by @dangotbanned in #3787
• fix(typing): overload in eval_block incorrectly showed True as the default for strict by @MarcoGorelli in #3855
• fix: import TypedDict from typing from python 3.15 by @mattijn in #3877
• fix: update typing_extensions dependency for Python < 3.15 by @daizutabi in #3881
• fix: Make .changed property optional in JupyterChart #3868 by @azjps in #3871
• fix(types): Change the height and width types of alt.Chart() from int to float by @joaopalmeiro in #3888
• fix: Repair vega export by @bobot in #3889

Documentation

• docs: Update LICENSE, fix copyright license year by @JasonnnW3000 in #3726
• docs: Add altair-upset link by @edmundmiller in #3786
• docs(example): Adds Confidence Interval Ellipses by @dangotbanned in #3747
• docs: Resolve geopandas.read_file(...) warnings by @dangotbanned in #3795
• docs: bump pyscript==2025.2.2 by @dangotbanned in #3797
• docs: fix broken links by @jannisko in #3802
• docs(example): Add Faceted map using Species Habitat dataset by @dsmedia in #3809
• docs: Add documentation for initial interval selection date ranges by @dsmedia in #3815
• docs: Update the waterfall_chart.py colors by @eitanlees in #3830
• docs: Clarify how order and on in the param section by @joelostblom in #3629
• docs: Improved docs on Transforms by @tempdata73 in #2655
• docs: More clearly illustrate parameter compositions by @joelostblom in #3628
• docs: new dataset source, from vega_dataset to altair.dataset by @mattijn in #3859
• docs: Correct some typos by @star1327p in #3904
• docs: improve docs how to return chart as html by @mattijn in #3849
• docs: Update the Lightning Viz link by @star1327p in #3839
• docs: Iris to penguins by @baldwint in #2231
• docs: docbuild warnings by @mattijn in #3850
• docs: Make the Code of Conduct link clickable by @star1327p in #3852
• docs: note within geoshape mark page to spatial data section by @mattijn in #3892
• docs: Remove whitespace after '*' so that text is rendered italic. by @thomascamminady in #3882
• docs: fix broken external reference URLs in examples by @dsmedia in #3898

Other Changes

• chore: Bump version to 5.6.0dev by @jonmmease in #3700
• ci: Temporal examples in vegafusion by @dangotbanned in #3702
• refactor(ruff): Apply TC006 fixes by @dangotbanned in #3706
• chore: fix ruff, mypy warnings by @dangotbanned in #3717
• ci: Switch from hatch, pip to uv in GitHub Actions by @dangotbanned in #3719
• ci(typing): Add bundled stubs to pyright.ignore by @dangotbanned in #3724
• ci: bump astral-sh/setup-uv from 4 to 5 in the github-actions group by @dependabot[bot] in #3727
• chore(ruff): Fix ruff warnings by @dangotbanned in #3736
• chore(typing): fix mypy>=1.14.0 warnings by @dangotbanned in #3739
• chore(ruff): Fix UP006 warnings during codegen by @dangotbanned in #3746
• refactor: Centralize Vega project versioning by @dangotbanned in #3720
• ci: Unpin pillow, allow >=10.0.0 by @dangotbanned in #3764
• chore(ruff): Update to 0.9.0 by @dangotbanned in #3766
• chore(ruff): Fix 0.9.2 lints by @dangotbanned in #3771
• chore: Add needs-triage to new bug reports by @dangotbanned in #3769
• test: Make skip_requires_pyarrow compatible w/ pytest.param by @dangotbanned in #3772
• build: Migrate from hatch to uv by @dangotbanned in #3723
• ci(typing): Disable mypy [annotation-unchecked] on examples by @dangotbanned in #3775
• ci(uv): Remove dynamic version from uv.lock by @dangotbanned in #3776
• ci(uv): bump mypy==1.15.0 by @dangotbanned in #3790
• ci: bump narwhals>=1.25.1 by @dangotbanned in #3792
• ci(uv): bump ruff==0.9.5 by @dangotbanned in #3799
• ci: bump narwhals>=1.26.0 by @dangotbanned in #3800
• ci: bump narwhals>=1.27.1 by @dangotbanned in #3807
• chore: Remove deprecated nw.from_native(..., strict=True) by @dangotbanned in #3811
• chore(typing): Follow-up fix _from_array_like by @dangotbanned in #3812
• ci(ruff): move exclude to extend-exclude by @dangotbanned in #3813
• chore: Add numfocus sponsor link by @joelostblom in #3814
• chore: Use organization-wide FUNDING.yml by @joelostblom in #3816
• chore: Bump vega-embed==7 by @franzhaas in #3829
• chore: Run typos and codespell against the codebase by @kurtmckee in #3840
• ci: bump astral-sh/setup-uv from 5 to 6 in the github-actions group by @dependabot[bot] in #3834
• ci: fix outdated ipython[kernel] dependency by @dangotbanned in #3861
• test: update test_datasets.py by @mattijn in #3857
• ci: add nightly builds system by @mattijn in #3858
• ci: fix mypy unused-ignore in tests by @m...

Release 5.5.0

The Vega-Altair team is pleased to announce the release of version 5.5.0. This version introduces several exciting new features and enhancements including a revamped theme system, a new renderer optimized for screen readers, and numerous type system updates that improve auto-completion and make it easier to integrate Altair into larger typed programs.

This release adds Python 3.13 and removes Python 3.8 support. It also includes a variety of documentation improvements and a range of important bug fixes.

Thanks to our maintainers (@binste, @dangotbanned, @joelostblom, @mattijn, and @jonmmease), returning contributors (@MarcoGorelli, @daylinmorgan, and @dsmedia), and first time contributors (@jpn--, @davidgroves, and @apoorvkh) for these improvements.

What's Changed

Deprecation

alt.themes

This release deprecates the alt.themes ThemeRegistry object and replaces it with an improved theme API in the new alt.theme module.
See the updated Chart Themes documentation for more information.

• Refactor alt.themes -> alt.theme by @dangotbanned in #3618
• Adds @alt.theme.register decorator by @dangotbanned in #3526
• Adds ThemeConfig (TypedDict) by @dangotbanned in #3536

Example of registering a custom theme

import altair as alt
import pandas as pd

data = pd.DataFrame({'x': [5, 3, 6, 7, 2],
                     'y': ['A', 'B', 'C', 'D', 'E']})

@alt.theme.register("my_little_theme", enable=True)
def custom_theme():
    return alt.theme.ThemeConfig(
        config={
            "bar":{"color":"black"}
        }
    )

chart = alt.Chart(data).mark_bar().encode(
    x='x',
    y='y',
)
chart  # enable default using `alt.theme.enable("default")`

Example of instant feedback while you define a theme config through Pylance in VSCode

Enhancements

Olli Renderer

This release integrates the Olli project to provide a chart renderer that augments chart visualizations with a keyboard-navigable structure accessible to screen readers.

• Add 'olli' renderer to generate accessible text structures for screen reader users by @binste in #3580

Example of olli renderer:

import altair as alt
from vega_datasets import data

alt.renderers.enable("olli")

cars = data.cars.url
chart = alt.Chart(cars).mark_bar().encode(
    y='Cylinders:O',
    x='mean_acc:Q'
).transform_aggregate(
    mean_acc='mean(Acceleration)',
    groupby=["Cylinders"]
)
chart

Expressions and Selections

Several improvements were made to Altair's expression and selection APIs:

• Generate expr method signatures, docs by @dangotbanned in #3600
• Support &, |, ~ on all ...Predicate classes by @dangotbanned in #3668
• Support datetime.(date|datetime) in Expression(s) by @dangotbanned in #3654
• Support datetime.(date|datetime) as a SchemaBase parameter by @dangotbanned in #3653
• Add missing float to IntoExpression alias by @dangotbanned in #3611

Example of combining predicates within .transform_filter

import altair as alt
from vega_datasets import data

source = data.population.url
chart = alt.Chart(source).mark_line().encode(
    x="age:O",
    y="sum(people):Q",
    color="year:O"
).transform_filter(
    ~alt.FieldRangePredicate(field='year', range=[1900, 1960]) 
    & (alt.datum.age <= 70)
)
chart

Example of using Python datetime.date for value in alt.selection_interval()

import datetime
import altair as alt
from vega_datasets import data

source = data.unemployment_across_industries.url
dt_values = [datetime.date(2005, 1, 1), datetime.date(2009, 1, 1)]

brush = alt.selection_interval(
    encodings=['x'],
    value={"x": dt_values}
)

base = alt.Chart(source).mark_area(
    color='goldenrod',
    opacity=0.3
).encode(
    x='yearmonth(date):T',
    y='sum(count):Q',
)

background = base.add_params(brush)
selected = base.transform_filter(brush).mark_area(color='goldenrod')

background + selected

Multiple predicates and constraints in Chart.transform_filter

• Support Chart.transform_filter(*predicates, **constraints) by @dangotbanned in #3664

Example of using keyword-argument constraints to simplify filter compositions:

import altair as alt
from vega_datasets import data

source = data.population.url
chart = alt.Chart(source).mark_area().encode(
    x="age:O",
    y="sum(people):Q",
    color="year:O"
).transform_filter(year=2000, sex=1)
chart

Bug Fixes

• Resolve multiple @utils.use_signature issues by @dangotbanned in #3565
• Relax dict annotations in channels.py by @dangotbanned in #3573
• Set charset=UTF-8 in HTML templates. by @davidgroves in #3604
• Replace unsafe locals() manipulation in Chart.encode by @dangotbanned in #3637
• Revise generated annotation order by @dangotbanned in #3655
• Resolve alt.binding signature/docstring issues by @dangotbanned in #3671
• Add missing @skip_requires_pyarrow(requires_tzdata=True) by @dangotbanned in #3674
• Don't materialise Ibis table to PyArrow if using vegafusion data transformer by @MarcoGorelli in #3566
• mypy 1.12.0 errors by @dangotbanned in #3632
• Resolve warnings in test_api.py by @dangotbanned in #3592

Documentation

Several new examples were added to the documentation

Example of using alt.when().then().otherwise()

import altair as alt
from vega_datasets import data

source = data.cars()

brush = alt.selection_interval()

chart = alt.Chart(source).mark_point().encode(
    x='Horsepower',
    y='Miles_per_Gallon',
    color=alt.when(brush).then("Origin").otherwise(alt.value("lightgray"))
).add_params(
    brush
)
chart

Example of using luminance in an expression to dynamically colorize text

import altair as alt
from vega_datasets import data

source = data.barley()

base = alt.Chart(source).encode(
    x=alt.X('sum(yield):Q').stack('zero'),
    y=alt.Y('site:O').sort('-x'),
    text=alt.Text('sum(yield):Q', format='.0f')
)

bars = base.mark_bar(
    tooltip=alt.expr("luminance(scale('color', datum.sum_yield))")
).encode(
    color='sum(yield):Q'
)

text = base.mark_text(
    align='right',
    dx=-3,
    color=alt.expr("luminance(scale('color', datum.sum_yield)) > 0.5 ? 'black' : 'white'")
)

bars + text

• Unstack area to render cumulative chart correctly by @joelostblom in #3558
• Change remote nick to origin and capitalize version commit by @joelostblom in #3559
• Update releasing notes to reflect that main branch is now protected by @binste in #3562
• Split interactive docs section into subpages by @joelostblom in #3561
• Update docs to use correct init value for selection_point by @jpn-- in #3584
• Add example with overlapping bars in a grouped bar chart by @mattijn in #3612
• Bar chart with labels coloured by measured luminance by @mattijn in #3614
• Adds example Calculate Residuals by @dangotbanned in #3625
• Adds Vega-Altair Theme Test by @dangotbanned in #3630
• adds info with step size/independent scale by @daylinmorgan in #3644
• Fix "Layered chart with Dual-Axis" (Method syntax) by @dangotbanned in #3660
• Fix inaccurate selection_interval signatur...

What's Changed

Enhancements

• feat(typing): Generate Literal aliases in channels overload(s) by @dangotbanned in #3535
• feat(typing): Generate Literal(s) using "const" by @dangotbanned in #3538

Bug Fixes

• fix: Raise informative error message if a non-existent column name is passed by @MarcoGorelli in #3533
• revert: Remove sphinx version constraint by @dangotbanned in #3541
• fix: Pass native dataframe to data transformers by @MarcoGorelli in #3550
• fix: Resolve Then copy TypeError by @dangotbanned in #3553

Documentation

• docs: Explain the title frame attribute by @dsmedia in #3537

Other Changes

• ci: bump ruff>=0.6.0 by @dangotbanned in #3539
• ci: Remove m2r from mypy.overrides by @dangotbanned in #3540
• refactor: Simplify SchemaBase.copy by @dangotbanned in #3543
• fix(typing): Resolve misc type ignores in schemapi.py by @dangotbanned in #3545
• test: Rename test to more specific chart_error_example__four_errors_hide_fourth by @dangotbanned in #3546
• test: Shorten test_chart_validation_errors test ids by @dangotbanned in #3551
• refactor: Replace an indirect SchemaBase import by @dangotbanned in #3556
• test: Fix deprecation warning from ipywidgets by @dangotbanned in #3557

Full Changelog: v5.4.0...v5.4.1