I would really like to include some kind of timeline information, and
perhaps a link to the above document, but I couldn't figure out how.
Any suggestions? The timeline seems to assume that you can predict all
your release dates and version numbers years in advance...

I'm not sure how to have a gant chart with a not-really precise dates. What I can suggest is to replace the version number by some text. like "new major versions Py3 Only" and "Long term support Python2"

Is that ok if I merge this and we see the timeline later ?

Something like that:

'Numpy':[
      {content: 'all NumPy releases fully support Py2 and Py3', start: '2017-01-01', end:'2018-12-31', py2:true},
      {content: ' New NumPy releases are Python3 only', start: '2019-01-01', end:'2022-01-01'},
    ],

Hmm, on further though, what do you think of something like:

'NumPy': [
    {content: '1.(x-1)', start: '2018-04-01', end: '2018-10-01', py2: true},
    {content: '1.x (last release in 2018)', start: '2018-10-01', end: '2019-12-31', py2: true},
    {content: '1.(x+1) (first release in 2019)', start: '2019-04-01', end: '2019-10-01'},
    {content: '1.(x+2)', start: '2019-10-01', end: '2020-04-01'},
    {content: '1.(x+3)', start: '2020-04-01', end: '2020-10-01'},
]

The actual dates there are made up of course, but I guess that's true of all the entries on the chart :-)

Thanks @njsmith . I'm going to merge this now - we can add timeline information later if you like.

I'd probably do the timeline for numpy with one bar saying 'Python 2 community support' to the end of 2019, and one saying 'New releases require Python 3' from the start of 2018.

Hmm, on further though, what do you think of something like:

Either are fine. I'm amazed by the positive/no-reaction reception on reddit/HN.