Currently I don't see that Flow edits from a mobile device are tagged in any way, at least not in a way that I can see publicly. It is probably very useful to check the metrics of Flow usage from mobile devices, so it should be tracked somehow.
The tag is added via ListDefinedTags and ChangeTagsListActive hook handler
I guess since Flow edits are not normal edits you will need to do something different or invoke this somehow :)
I just confirmed this bug on Portuguese Wikipedia:
was made from mobile but it has no indication of that fact (either on that permanent link, or the recent changes or my contributions).