These are patches for various Firejail versions for the security bug reported by Austin Morton
on May 21, 2019:

    Seccomp filters are copied into /run/firejail/mnt, and are writable
    within the jail. A malicious process can modify files from inside the
    jail. Processes that are later joined to the jail will not have seccomp
    filters applied.

The original discussion thread: #2718
The fix on mainline: https://github.com/netblue30/firejail/commit/eecf35c2f8249489a1d3e512bb07f0d427183134