[arp242]

The 7th version of the Scheme standard/specification, basically. There's a "small" and "large" version of it, for different use cases/preferences (there's a bit of drama behind this: R6RS introduces a lot of "large" features that many implementers felt were too "bloated", which was eventually resolved by splitting the standard in small/large variants).

[all2]

It seems like "core language" vs "standard library" almost. The Large spec includes things like lists, vectors, streams, and generators [0].

[0] https://practical-scheme.net/gauche/man/gauche-refe/R7RS-lar...