I think it's used for file level restore on S3 enabled backup. It's not crucial as long as you don't need to restore individual files on S3, obviously.
@julien-f is there a way to avoid this dep manually in order to build the rest of XO?
FreeBSD install was already documented officially: https://xen-orchestra.com/docs/installation.html#freebsd
You could have test to use HTTP instead of HTTPS to see if perfs are improved
New XO backup code will come in few releases that will speed up things
Quiesce snapshot: it's not needed for Linux VMs because of the disk driver automatically handling this.