Both rules check for invalid format character in % format style string.

The implementation is almost the same:

F509

PLE1300

There's one difference which can be noticed when an implicitly concatenated string is used. F509 looks at the concatenated string while PLE1300 looks at each part of an implicitly concatenated string. Refer to https://play.ruff.rs/6efd9945-2a3b-43e4-b9b7-a8d041b98318.

Reference:

• F509 https://docs.astral.sh/ruff/rules/percent-format-unsupported-format-character/
• PLE1300 https://docs.astral.sh/ruff/rules/bad-string-format-character/