Windows shell extensions such as context menu handlers. Along with my GPU driver I have injections from LibreOffice, 7-Zip, and Notepad++ to name a few.

You'd think they'd only need to hook into Explorer.exe but alas no, they show up in every process. I guess because of the file picker dialog which is an embedded Explorer window running in the host process.

And perhaps a reason why Mozilla wants to hurry and get off of Windows 7.