Google Summer of Code 2021 => Looks good!
I must say I'm pretty excited by the list of proposed topics, especially the shortcut one and the copy/paste one.
But all of them really.
If they are all implemented, I can't think of any other subject for which a basic level user could think, oh that piece of software is unfinished.
(Well except insert mode like Dorico but that will be for GSoC 2022 isn't it ;-) )