Maybe it is already possible, but I did not find it after a search on the internet and the forum.

Wouldn't it be lovely to add comments or notes for internal use in the timeline (or anywhere in the project - haven't found any place in the editor to add a comment) ? It would help a lot in creating a good workflow if different people are involved. But even for single user it can be very handy ! I'm currently working on a scene I need to make one picture of and I arranged everything so that frame 56 is the one (allowed me to play with the animations of the different actors). Now I need to keep that frame number somewhere written external, otherwise I would just add it in the project and forget it forever !

On project level would be good enough, but on object level would be even greater !