How does FileZilla Portable handle the 32/64-bit update in 3.10.3

3.10.3-beta1 (2015-03-14)
New features:
FileZilla is now also available as 64bit Windows program. Users of 32bit FileZilla on 64bit Windows will get automatically migrated using the auto-updater

How does FileZillaPortable handle installation and update with this new feature added?

Since it is portable, does it just install and use 32-bit for the best compatibility between different systems?

Does it install 64-bit based on the initial install prep-system?

Does it install both 32/64-bit executable files and runs the appropriate one based on the system that launches FileZillaPortable.exe?

When "Check for Updates" is used, does it always keep 32-bit or does it auto-detect the system that checks for the update as the release notes seem to indicate and FileZilla Updater will update a 64-bit system using the FileZillaPortable to 64-bit as well?