language agnostic - What is "vendoring"?

Question

What is "vendoring" exactly? How would you define this term?

Does it mean the same thing in different programming languages? Conceptually speaking, not looking at the exact implementation.

Answer 1

Based on this answer

Defined here for Go as:

Vendoring is the act of making your own copy of the 3rd party packages your project is using. Those copies are traditionally placed inside each project and then saved in the project repository.

The context of this answer is in the Go language, but the concept still applies.