It can, if your bank supports Spectre (which apparently is a common API service for banks). It's a bit awkward, you have to sign up for a third party to do it, but worked well for the three months or so I used Firefly.

Here are the docs: https://docs.firefly-iii.org/en/latest/import/spectre.html

(For what it's worth, now I use Pocketsmith, a NZ-made Mint clone that I'm pretty happy with.)