Looks important at least from the "don't leave stuff on disk" forensics angle?

Trac:
Keywords: N/A deleted, tbb-disk-leak added

I encounter similar behaviour since (at least) the first 8.5-alpha version of Tor Browser. Sometimes those files are created. When TBB is closed the remain in /tmp/

On my system they are either 9308406 or 9477406 bytes large. strings on one of the files show the following SO files:

tor-browser_de/Browser/libnspr4.so
tor-browser_de/Browser/libplds4.so
tor-browser_de/Browser/libplc4.so
tor-browser_de/Browser/libmozsandbox.so
tor-browser_de/Browser/liblgpllibs.so
tor-browser_de/Browser/libnssutil3.so
tor-browser_de/Browser/libnss3.so
tor-browser_de/Browser/libsmime3.so
tor-browser_de/Browser/libmozsqlite3.so
tor-browser_de/Browser/libssl3.so
tor-browser_de/Browser/libmozgtk.so
tor-browser_de/Browser/libxul.so

Yes, I see these files too. I am running Tor Browser 8.5a6. What is causing them?

Those files are Selfrando's memory layout files. See: https://lists.torproject.org/pipermail/tbb-dev/2017-May/000537.html ff. for further information.

Trac:
Parent: N/A to #23073 (moved)

We removed selfrando support in bug 30377, thus this is a WONTFIX.

Trac:
Status: new to closed
Resolution: N/A to wontfix