Using gridsync 0.4.1 with a paid s4 account on GNU/Linux (BuildID[sha1]=28ba79c778f7402713aec6af319ee0fbaf3a8014). Tor is enabled and there are direct connections from the gridsync application to Amazon ec2 to the host ec2-52-6-180-137.compute-1.amazonaws.com.. The host name wormhole.leastauthority.com resolves to 52.6.180.137 and resources/config.txt defines relay = ws://wormhole.tahoe-lafs.org:4000/v1 as the wormhole server. This IP and port match the Tor proxy bypass on my system:

gridsync  18326 user   72u  IPv4 698349      0t0  TCP 10.0.0.6:50130->52.6.180.137:4000 (ESTABLISHED)
gridsync  18326 user   79u  IPv4 700071      0t0  TCP 10.0.0.6:50132->52.6.180.137:4000 (ESTABLISHED)
gridsync  18326 user   81u  IPv4 699385      0t0  TCP 10.0.0.6:50108->52.6.180.137:4000 (ESTABLISHED)

I understand that Tor support is experimental and wanted to warn others that the rendezvous process, as well as Gridsync, does not appear to be protected by Tor at this time. This is persistent even when magic-wormhole isn't in active use. It appears after the use of magic-wormhole and it persists until restarting gridsync.