It is similar in nature to Universal Media Server but specifically designed for the PlayStation 3 entertainment system.
PS3 Media Server 1.53.0 Changelog:
Fix global custom MEncoder options
Re-fix NPE when toggling HTTP Engine V2
Fix startup for symlinked PMS.sh (#1356) (thanks, Matthijs!)
Added documentation to PMS.conf (thanks, Hagar!)
Updated JNA to support multiarch directories on Linux (#1152)
Added option to select and force the default renderer
Fixed Samsung 2012 TVs timeout (thanks, troop!)
Added support for D-link DSM-510 (thanks, glenrocks!)
Updated MPlayer build script to SB32
Fix "value too long" SQL exceptions
If renderer has not specified a maximum height/width, default to 1920x1080
Initial fix for Samsung 2012 TVs (thanks, troop!)
Linux: load system-wide defaults from /etc/skel if user's profile not found
Added recognition for AcePlayer app (thanks, md.versi!)
Fix parsing of [real] in plist preventing iPhoto libraries from working
Added Plugin development guide (thanks, glebb)
Language updates: added Arabic, added Hebrew (thanks, zvi-yamin!), CZE translation update (thanks, valib) Layout support for right-to-left languages added
Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
Thats exactly what it is Since Shagrath looked like he had no time for it anymore and he hadn't updated it for a very long time there has been a forked 'community patched' version. This has also been updated to include the new update.