Since upgrading to AS 4.1 from 4.0 I get the event log message
Plugin Error: Plugin "Install Apk" is incompatible (supported only in IntelliJ IDEA).
on starting AS.
Yes, this is like a previous report1, but this appears to be a bundled plugin. I don't think it's anything I've added, nor can I find anything obviously out of place either in the list of plugins under settings nor in the plugins directory.
Installing APKs does indeed not work, so it is a problem rather than a nuisance.
How do I track down where it's coming from, and even better, fix it?