Four items modify selection, the last one - delete selection - the list itself.
The effect of Select All, Unselect All and Invert Selection is obvious: Select All selects all items of the list, Unselect All unselects all items. Invert Selection makes selected items unselected and vice versa.
Select Points by keywords selects all items matching the given words; the match is performed against both name and description of each item.
Delete selections removes selected items from the list and from map as well.