Optional, per-directory OWNERS files are common, and most VCS frontends (Github, Bitbucket, etc.) can be configured to prevent merges without approval from the owning team(s) or DRI(s).
PRs that intersect multiple teams' ownership would require handoff of everyone impacted. So a team updating the company-wide "requests library" (or an equivalent change), with a wide blast radius, would be notifying everyone impacted and getting their buy-in.
Optional, per-directory OWNERS files are common, and most VCS frontends (Github, Bitbucket, etc.) can be configured to prevent merges without approval from the owning team(s) or DRI(s).
PRs that intersect multiple teams' ownership would require handoff of everyone impacted. So a team updating the company-wide "requests library" (or an equivalent change), with a wide blast radius, would be notifying everyone impacted and getting their buy-in.