From Nextcloud 13 it is integrated now, but with a own different file browser,
here you still can search and sort in the default file browser and have the clipboard.
The original repository is also unmaintained for almost over a year,
so here is a version which could possibly work in further updates.
Minimal clipboard feature for the files application. Allows to copy and move files between directories.
Extract the release in your apps directory and rename it to files_clipboard.