And not show any modules.
There is a preference for that under Privacy->Show My Modules
And why these two out of all the others? Thanks!
The Collection is a special favorite like function.
If you click on the suitcase icon on modules in the module browser that module will be added to your collection. To not have to search for it every time when planning different versions of your modular the modules of your Collection are available under the tab menu My modules.
I guess you clicked on that suitcase icon of the 2 modules not on purpose.
Unicorn users (You, thank you!) can also add every module of a rack to your collection. (Top left navigation: Edit->Add all to My Modules)