Awesome mod. Its installed on all my games now.

For anti-trolling. So trolls cant create garbage tasks without getting banned.

Also ability to restrict create/mark complete/assign tasks to admins through the permissions and groups menus.

Hi,
glad to hear that you like it :)

Showing who created/modified a task is actually in the next version. This should be finished in the next week or so.

I have never used the permission screen (so far I didn't even know it existed).
I understand the idea, though. Especially for public servers this might be interesting.
I created an issue for this https://github.com/JonasJurczok/factorio-todo-list/issues/72

Do you have any pointer to mods that have this kind of authorisation control?
Browsing the API to this point got me nothing to work with...

I linked the API in the ticket. It should actually be relatively easy to do.