A little late to suggest this, but I’d love to hear about KDEnlive greatly increasing the amount of automated tests done before releases.
With each big release there’s always a couple bugs that can break projects(new or old), and those can take weeks to be fixed, leading to multiple problems…
Check this page, and perhaps you can help with test scripts or bug triaging …
And of course there are always the nightly builds that can be used by anybody to test for regressions with their own projects (which is really helpful as it puts Kdenlive through the motions using a broader scope than what the dev team can do).