I put the link to the specific text (for Chrome based browsers only) to that post now. However, I linked to the wiki article in question in my previous post and my reference to the previous commenter about S4 being T4 was a reply to the link they posted directly above my reply, so I think it was not that hard to get from context (after all, they corrected their comment on Github as I now see :-)).
Edit: Could the part of the debate about mtb:scale be divided into a separate topics? If we arrive at some agreement about some possible inferences, it wouldbe put to the wiki.
After reading the definitions back and forth, it seems to me that a resonable assumption is
S4 and higher is probably at least T3.
S3 is probably T2 (but probably not higher).
S2 and lower is no higher than T2, quite possibly T1 (so no assumption should be taken, only possibly in reverse case should some router decide not to route over paths without sac_scale for fear ofthem being too difficult).
It should always be recommended to add both mtb:scale and sac_scale and point out that these assumptions are mostly correct, but not alway.