[Evolution] evolution to do list

[Jaap <jjb softskills nl>]

Hello,

In my evolution (Fedora 32) is a to do list. It is in the main window 
right side

I guess it has something to do with tasks (evolution taks I mean)

But in evolution manual no hint to any use of to do list.

Where is to find help for evolution? mailing list did not give anything 
in that direction..

thank you

Jaap