I have to agree with cave_troll.
Did you know that P8 in Derbyshire used to have 2 fixed ladders: one bypassing the second pitch, which was only removed a few years ago and a second on the first pitch?
Did you know that Garlands pitch in Giants Hole also used to have a fixed ladder?
OK - not all that useful, but these little bits of information were gleaned from old Orpheus CC newsletters from the 60's (no - I'm not a sad git poring over old newsletters - my girlfriend is helping prepare a 50th Anniversary publication for the Club - probably just in time for the 57th Anniversary! This involves going over old pulications, newsletters and getting information on the Club's history.).
There is a wealth of information in periodicals, journals, newletters, etc. etc. which are catalogued and accesible, some easier than others.
Yes, pages from the Internet are archived in some manner (at least some of them) and you can search using Google, etc but all this infomration is very disparate and could easily be lost.
Search for "petzl stop clutch and plummet" on Google and you get exactly one hit:
BURTON SNOWBOARDS
Burton Clutch BagColor Shown

uneFeatures:Rip-Stop Patterned Corduroy Magnetic
... of Thermacore™ that’ll keep you stoked when the temperatures plummet. ...
www.muddybootsmercantile.com/ USOUTDOOR/BURTON-SNOWBOARDS.html - 120k - Cached - Similar pages
I recently came across an article on SRT using natrural belays, writen in the US and available on a web site. It quoted a letter from myself to Descent written in 1986 (Descent has an index of articles, letters, etc). How likely is it that this message I am writing now could be found if necessary in 2024 (19 years hence) if anybody had a use for it (pretty unlikely!)? But I bet you could still trace that letter from Descent...