Upstream

“Upstream” refers to someone that provides some kind of information to us. Usually, this means

• … an “upstream” software package is provided by some other person or group, but then we might make changes to it;
• … an “upstream” source of art or music provides things that we might integrate.

Note, that integrating, bundling, aggregating, or synchronizing count as “modifying” the upstream information, so we can't use (for example) music that has the Creative Commons “⊜” (circled equals sign / no modification) rule.

See Creative Commons and so forth.