This is an excellent subtitle, and comes with two different ones.

One is the speech only, the other is for "hearing impaired" so adds other audio cues that are not spoken.

Yes, I think so! I'm hearing impaired and really appreciate these versions.
But to be clear in case it wasn't obvious: I didn't write these subtitles. I've only extracted them.

I'm trying to imagine which cues are used: Squelching. Squeaking. Slobbering. Gulping. LOL JK

Kind of music being played, traffic noises, things like that. In professional subs that is often done, or say "Inaudible" if people are talking but you can't hear the voices.

I know that. They do that with all regular movies. I was more curious as to cues used in porn movies. '70's porn music playing' 'Bed squeaking loudly' 'Heavy thumping on ceiling' 'Vibrator buzzing' etc...

No, there are not that kind of subtitles :)
What you have in HI versions are informations to help understanding the story. As Mushroom said, "inaudible" is a very important information because as an hearing impaired person, if I see someone speaking, I'll try to understand (pause and rewind). If I see "inaudible", I know I don't have to.

Same for sounds like "door opening" to understand why characters suddenly stop speaking (was it because someone screamed outside, something felt on the ground, ...)

[Laugh], [Giggling], [Panting], [Moaning], [Sucking sounds], [Slurping sound], [Kissing sounds], [Breathing sounds].

Many PornHub videos that have subtitles, are this way, I don't know if they have something automatic to make them. I don't understand their usefulness either, but they exist. Like for example this one:

https://www.avsubtitles.com/subtitles.php?subid=4865

IKR! I'm not making light of the hearing impaired. (I can still hear the IED that went off close to me. I was lucky) I'm just making light of these cues in a porno. Sort of like the Braille keys on a drive-thru ATM machine. (Check the next one you see. Go ahead!)

Want to know how bad even subtitles in a professional production can be? I was rewatching the TV series "Heroes" from a decade ago, and the character was entering a bar and the subtitles described the music as "Country Music Playing". As the song was "The Chain" by Fleetwood Mac. Which is not even remotely "country".

Either the subtitler or editor did not even know what the song actually was, or did not care and just threw in "country". Where they should have said it was "Rock". Or even better, given the lyrics as it was a clue for what was to come.

Overall it's fine, but there are a few timecodes that don't fit well with some dialogue.