The KDE4 version of keditbookmarks had Undo and Redo actions (in their expected place in the "Edit" menu). This meant that an unintended delete of a bookmark or folder could be reversed. Now in the KF5 versions these actions appear to be not present. This means that deleting a bookmark happens immediately without confirmation, with no way of undoing the action or recovering the deleted bookmark. The delete action should either prompt for confirmation, or it should be able to be undone. This is keditbookmarks version 5.0 started standalone (i.e. not from within Konqueror).
keditbookmarks build from the new repo commits.kde.org/keditbookmarks (splitted fron kde-baseapps) has Undo + Redo action, they wotks as properly as in the kde4 version. Please update + try again
Cannot confirm either. Undo worked after delete in KF5 version of keditbookmarks, started from Konsole. If you did compile keditbookmarks yourself, it is possible that you did not install it correctly. In this case, it might not find the required ui.rc files and therefor lack some menu entries.
Works perfectly in the split KF5 version. Apoogies for the spurious report.