Cache is generally preferred - but you may from time to time - for any reason you can think of - want to clear it.
The system keeps track of recently used files - e.g. saved as or opened - these files is usually listing the Recent file pane in the system file selection box as pointed to by @xabbu above.
Applications may keep their own history inside their configuration file(s) - in which case you need to use the applications clear recent items function or locate the config and remove the data.
The System Maintenance wiki page linked @banjo above is a great page to get familiar with your system and the various hidden configuration files and folsers.
As noted the ~/.cache folder can be removed at any random time without severe consequences.
rm -rf ~/.cache
Thank you. Is this wiki link the ongoing, updated manual? I’ll certainly start using that. There’s one more thing that keeps happening that I’ve not been able to solve but I’ll post another question on that one.