With moving devices around between Hubitat, SmartThings, and Home Assistant, I have some Past Log entries for devices that are no longer connected to Hubitat, or have been re-connected and have another set of logs under the same name.
Is there a way to remove the orphan log entries, or will they eventually go away on their own?
Past Logs will eventually disappear on their own, subject to the automatic purging that happens when they reach the size limit. The only other way to remove them is as an option (new in 2.3.3, or I think really the updated Diagnostic Tool) during a soft reset, as they are not stored in the database (so won't be erased but also won't be restored if wiped in this way). Probably more than I'd do for just this, but one option if it bothers you enough.
Past Logs are purged based on total size, not per device, so that will not happen. The logs will remain, even for a removed device (or app), until that point, however.