I'm a software developer for open source projects I use myself.
I started using OBS to live stream sporting events. For these live streams I wanted to do slow motion replays.
In OBS I started creating my own LUA script for replay and making changes to OBS allowing for playback at different speeds. Having made those changes I still did not like having to wait for the replay to be saved to disk, so I started making my first OBS plugin called Replay Source. With that plugin being published on the OBS forum I started adding features on request.
To let the replays appear on stream I used an OBS plugin called motion-effect. Not totally happy with the resources it used and the effect it created I made the Move Transition plugin, which became one of the most popular OBS plugins.