The TXT component version is stored in the DMI table and you can decode it like this:
Which prints 1.18.13.0 on my 12th gen Framework laptop, after the update, and thus matches the version specified in the announcement. 
(I couldn’t include that small shell one-liner in this post because of a misconfigured discourse filter: Discourse forum somewhat broken, I can't post the command to show the linux kernel version)
I have no idea what ‘SI’ even stands for.
Web-searching that version turns up some references to Intel firmware-support-package (FSP) versions - but who knows …
Hm, there are a few sources that counter this argument in another thread:
(see also the few follow-ups after comment post)