Aegisub is a high quality open source Annotation Editor and Karoke template generator
License: GPL and BSD
Upstream has been contacted: No (they’re gone )
Aegisub was ranked as the highest quality open source video annotation editor and probably the only FOSS karoke making app. Source: https://www.ubuntupit.com/best-subtitle-editor-for-linux/
This software is still in the Repos of Fedora 34, Arch and Ubuntu 21.04. But it has not been updated since 2015 and is endangered of deprecating; because it is still GTK2. I am hoping that Flatpak technology will save this app from deprecating. In my opinion It would be a monumental shame if tens of thousands of lines of code went down the drain. Flatpak has the ability to rescue quality open source apps that are endangered. This is software that we cannot allow to die.
I am learning how to build Flatpak’s myself so I would not be surprised if I am the one who makes a flatpak of this.