Signal will let you export but not choose where to export to, so if you're running out of space on your phone and add an SD card to back up your signal database or export media, tough luck because the output destination is hardcoded. For your security, of course.
"Signal Export" is account metadata without messages and images! And the backup is encrypted, you need some third party tool to decrypt it and that does not work for me and i would not consider a company satisfying data portability laws if the export depends on compiling c++ from a third party. And if you just want to move your signal account from android to ios that wont help you either as its not possible to restore and android backup to an ios signal app.
