PulseAudio now supports using memfd for shared-memory support when the daemon's enable-memfd=yes configuration option is present. Memfd is used in place of POSIX SHM for shared memory. The Memfd support is described by the PulseAudio developers as "to share pages between processes in an anonymous, no global registry needed, no mount-point required, relatively secure, manner."
Implementing Memfd support in the PulseAudio audio server is a stepping stone towards allowing better integration with per-app containers, such as sandboxed applications via XDG-App.
The code landed in PulseAudio earlier today for memfd transport. Memfd has been around for a while and mainlined since Linux 3.17.