I recently heard this and I think I like it! [name_f]Do[/name_f] you?
I like it as a GP.
It is definitely a super cute one. Thanks!
I like [name_u]Harper[/name_u] more as an alternative.
I think it would be mistaken for [name_u]Harper[/name_u].
[name_u]Harbor[/name_u] for a girl? NO! Not even for a boy. Why? It sounds so silly.
I like it only as a middle name.
I knew someone called [name_f]Arbor[/name_f] and it just doesn’t have a nice ring to it, in my opinion. Maybe it depends on your accent though - where I’m from the r is pronounced very strongly.
I’m one of those people who like [name_u]Harbor[/name_u] — for years actually — and plan on using the name myself, (where in my case, I want to use it for a boy.) but definitely, it’s cute on a girl and I feel it’s useable. But I might be biased since I plan on using it for my son in the future but if you like it, save it to your list of names you’d use in the future! It’s definitely cute and darling on either gender imo so go for it 
I love [name_u]Harbor[/name_u], though I think I’d consider it a GP. Despite it’s similarity to [name_u]Harper[/name_u], I can see it on either gender. I like the combo [name_f]Madeleine[/name_f] [name_u]Harbor[/name_u] or [name_u]Harbor[/name_u] [name_f]Madeleine[/name_f].
I quite like it and definitely think it usable. Like others, I also think it could often be mistaken for [name_u]Harper[/name_u], so I guess it depends just how much that might bother you/her?