Name: srt
Product homepage: https://pypi.org/project/srt/
Justification of Inclusion: srt is a tiny, featureful python library for working with SRT files. It claims to be around 30% faster than pysrt in typical workloads. It even claims to be able to parse and fix many broken SRT files.
Open source: Yes, MIT license
Link to most recent source tag: https://github.com/cdown/srt/releases/tag/3.5.2

srt is a candidate to replace pysrt. There is only one package - subliminal - which depends on pysrt. I'm currently working on a patch to swap that over to srt as well.