Literally that.
Since the development team would and will be focused at KSP2, could you give us the source code, so we might look at it and, maybe, fix some things in it to make KSP1 a better game.
I'm begging you to do it.
To anyone still wondering why Open Source is needed, google about the ongoing Unity drama about the Unity Runtime.
I had warned months ago that we were on the verge of an Inflection Point here. It's not time to start to move?