Storing a list persistently

Howdy! I was hoping to make a library that can monitor the space for dead links and display them in a report, or the count of dead links inside a button (or wherever else).

However, I would want it to only periodically perform the check (e.g. 1/day) and store the results, rather than perform the test whenever, say, the virtual page or button widget is loaded. But I’m not sure of the proper way to store the data persistently. Frontmatter doesn’t have a good way to edit lists of data yet (we can only add currently) and in any case I don’t want my personal space to be writing anything to file that would then make the library look like its been changed.