It's not easy to find vanilla or Boom demos (99% of all Prboom/+ demos, for a good reason) when the lists don't mention the demo version and the player can't tell what's comparable from the version of the engine in PrBoom's case because PrBoom is "many engines in one".
Andy Olivera said:
And finally, the display of the engine used for recording is simply to show what port is guaranteed to play back the demo. The DSDA exists to compile all the demos into one place so they're easy to find and view. It's up to the viewer to determine what's 'comparable', the 'real' record, etc.
So PrBoom is the problem in the list, because all other engines are straightforward in this respect (except maybe Boom's Doom compatibility could also be noted, although I'm not sure if any demos use it... a mere note will do there). Opulent started the DSDA before PrBoom came to the scene and he was listing the compatibility level of the demos, although only in the descriptions below, probably because the mention was a late addition. As far as I'm concerned, a "PrBoom-plus v126.96.36.199 demo" is a demo recorded with that engine's default compatibility, not one of the lower compatibility levels, such as 2 or 9.
Compare the Scythe pages from the old and new DSDA; a bunch of data that was at the bottom was eliminated and not fully integrated into the list.
For the lists to be complete, they need the compatibility level for any PrBoom/+ demos. If you think this data may somehow clutter the lists, you could even note it in a systematic and non-intrusive way. For example, "PrBoom-plus 188.8.131.52/9" could mean "PrBoom-plus version 184.108.40.206 -complevel 9". You could explain this somewhere, such as at the bottom of the lists or on the info page. If you explain it on the info page, you could note what each compatibility level means for each group of PrBoom versions, as it changed through the years. Boom compatibility was initially 3, then 5, and is now 9, for example.
On the Info page you have links to various source ports. It would be wise to have a link to the PrBoom+ site there, instead of some older version (you have 220.127.116.11 there, which is kind of old already and may have Boom compatibility bugs), to encourage people to use the latest stable version. The same could be done for all the regularly maintained ports.