@PeterJones Thanks for the suggestions: I didn’t realize the bit about -noPlugin. I ended up installing the newest version of np++ first, and then realizing the reason I hadn’t been using the x64 is because there are still plugins that don’t work with it, so installed latest x86 and went through each plugin.
Not sure what to make about the file paths information, since I’m only interested in why notepad++ was opening this specific file, in IE’s temporary directory…
Anyway, for anyone else who is (unreasonably?) paranoid, the culprit is “JSTool”. And, rather marvelously, it’s actually got an option that seems to control this, “Disable new version checking” (which, of course, makes sense why it’s accessing some temp internet dir file).
I really appreciate the help (and pointers; plugins completed skipped my mind here). This is a trivial thing, but I’m actually pretty skittish about files being open I didn’t explicitly expect. (And as an aside, tend not to let things write to my SSD; on windows, everything’s reparse pointed elsewhere).
tl;dr np++ is well behaved and lovely, JSTools hits counters.dat for its updates and has facility to disable the behavior. ;) TGIF!
Edit: Is it possible to change this thread topic to “SOLVED” or the like? Feeling like such a newb…