Those are the "Places" found in Dolphin's sidebar or Open/Save dialogs.
This does not include the Search for / Recently saved entries and nor does it include removable hard drives, it's only the static places the user can have in here.
Depending on the number of places the menu can get quite large,Only seen Dolphin having this category. thoughVerified that the places are opened with the respective application - for testing I added the flag to Gwenview and had Gwenview open e.g. It's shown both for a launcher (not running) or a window (adds the maximize/minimize/close/etc entries which makes it even longer) :/the Pictures folder.
Only seen Dolphin having this category. Verified that the places are opened with the respective application - for testing I added the flag to Gwenview and had Gwenview open e.g. the Pictures folder.{F1185194}
{F1185194}511472}
(colapsed view - as you can tell, the "Downloads" place in the upper screenshot is not in the collapsed view as I clicked the Projects entry more often)