[MangoToupe]

Where might one look to find examples of such code? I've never found algol outside of wikipedia

[geocar]

https://rosettacode.org/wiki/Category:ALGOL_68

https://github.com/search?q=algol68&type=repositories

Without knowing what your interests/motivations and backgrounds are, it is hard to make good recommendations, but if you didn't know about rosettacode or github I figured I should start with that

[MangoToupe]

What I'm taking away from this is that there's absolutely zero code of interest that is Algol 68

[geocar]

Interests vary!

Just because you can’t find something interesting doesn’t mean it isn’t interesting.

That lesson once learned pays dividends

[jemarch]

You can find some modern Algol 68 code, using the modern stropping which is the default in GCC, at https://git.sr.ht/~jemarch/godcc

Godcc is a command-line interface for Compiler Explorer written in Algol 68.

[pjmlp]

Old papers and computer manuals from the 1960's.

Many have been digitalized throughout the years across Bitsavers, ACM/SIGPLAN, IEEE, or university departments.

Also heavily influenced languages like ESPOL, NEWP, PL/I and its variants.