Problem

The 3rd party package listing is getting unwieldy, making discoverability difficult. It also requires creating & merging a PR that manually changes the page.

Proposal

Pypa has classifiers users can filter on. 3rd party package devs could add the classifier to their packaging, and then users could filter on PyPA for domain specific Matplotlib packages. The 3rd party package page would then be updated to link out to the PyPa list and document how to add the matplotlib classifier to the package. Optimally, conda would also adopt tags and a link to that list could also be added to the page.

Downsides

Might create a moderation load in terms of making sure packages tagged matplotlib are actually matplotlib & not trying to park at the tag, but there's probably a low risk of this.
Also loses some of the community flavor of the third party package page, but that could maybe be rectified by intermittently scraping the pypi and conda pages to populate a sort of gallary of packages.

To Dos

packager to-dos

• request classifier from PyPa: Request trove classifier: matplotlib pypi/support#232
• PyPa grants Framework :: Matplotlib classifier
• open issue on conda asking for trove classifier analogue: PEP 301 (classifiers) conda/conda#9716
• conda implements tags
• request matplotlib tag

doc to-dos

• create new ecosystem page
• link to PyPa list of packages with Framework :: Matplotlib
• link to conda & conda forge list of packages w/ matplotlib tag
• explain how to add Framework :: Matplotlib to setup.py
• explain how to register w/ conda
• stress that they should have a picture and explanation in their readme

deprecation plan

• open PRs on packages listed on third party package pages (sprint or good-first issues):
  • add Framework :: Matplotlib classifier to setup.py
  • add whatever conda's standard is
• heavily advertise new policy
• discourse/mailing lists/tweets
• blog post stressing ecosystems
• deprecate current 3rd party package page

amendment

This does not have to wait on conda adopting the feature, especially as many of the projects currently listed on the 3rd party package page have registered the classifier.