It’s one of the default shortcuts:
Toggle Contents in the sidebar. When I hit it, this empty page called Contents.md is created with no explanation.
I see from Rename Contents to Favorites - #25 by Swagmen_toSweden that it was supposed to act like a pinboard which has now been changed to Favorites?
So why is there still a keyboard shortcut for opening Contents in the sidebar?
AFAIK you are just supposed to list there the main contents of your graph and it’s shown on the sidebar for convenience.
The Favorites section in the left menu is just a list of pages. On Contents.md instead you can place whatever you want like in any Logseq page.
For example if you use the agenda plugin you can show its widget there.
So basically Rename Contents to Favorites - #25 by Swagmen_toSweden was not addressed. And it still should be renamed. That issue was incorrectly archived then.
Just posted Rename Contents to Pinboard