Objects of this type are created by GG.
The object GrassmannianVariety is a type, with ancestor classes EmbeddedProjectiveVariety < MultiprojectiveVariety < MutableHashTable < HashTable < Thing.
The source of this document is in /build/reproducible-path/macaulay2-1.25.05+ds/M2/Macaulay2/packages/MultiprojectiveVarieties.m2:3993:0.