keyboard mappings, dead keys, which map is which [closed]

i’m not as salty as some ppl but i know my way around a manual install of linux

something that’s always bothered me tho and i can’t easily find sources on is the differences btwn all the diff english keyboard maps

the following 3 keyboard mappings titles r taken from the guix system installer

and represent a particularly ambiguous subset of the ambiguous english options

"English (intl., with AltGr dead keys)"

"English (US, intl., with dead keys)"

"English (US, alt. intl.)"

when they say “alt.” (in “alt. intl.”) is that an abbreviation of “AltGr” ? is it an abbreviation of “AltGr dead keys” ? or do they mean “alt” as an abbreviation of the word “alternative” (in which case wtf does that mean) ?

is “with dead keys” an abbreviation of “with AltGr dead keys” ? or does it refer to smthn else entirely ?

what the fuck is the difference btwn these three

and what obvious resource was i supposed to already be familiar with in order to not be confused by this

thank u very much to any salty sailors of the system configuration seas out there that r able and willing to lend some clarity to the rest of us on this topic

for me but more importantly for anyone else searching for this answer in the future