Oh! When I see "roaming" in a tech context I think of *devices* that roam, not people roaming over *multiple devices* (and thus wanting to share data from one to another). Thanks; that makes more sense now.

Before this migration I synced Firefox with another device (the aforementioned Win10 tablet, which was an accidental freebie. I had thought that would let me "clone" a session -- start Firefox over there with all my tabs, bookmarks, etc. What it actually did was give me access to my synced tabs, one at a time, in a random-seeming order. Fortunately, I didn't need to fetch any of that back to the machine that was being migrated.