After recent conversion of log leafNodes to valueless, a typical firewall rule entry that enables log looks like so:

set firewall ipv4 forward filter rule 101 log

However, the chain level defaults log looks like so (with redundant enable prefix):

set firewall ipv4 forward filter enable-default-log

We can rename enable-default-log for consistency with rule-level entries like so:

set firewall ipv4 forward filter default-log