A company I worked at also did this, though there was no limits. Some folks would choose to spend the whole week working on a larger refactor, for example, I unified all of our redis usage to use a single modern library compared to the mess of 3 libraries of various ages across our codebase. This was relatively easy, but tedious, and required some new tests/etc.

Overall, I think this kind of thing is very positive for the health of building software, and morale to show that it is a priority to actually address these things.