Repository protection is the set of controls that guard source code from unauthorized changes, review bypass, and accidental or malicious exposure of sensitive data. In platforms like GitLab or GitHub, it includes branch protection, merge approvals, access limits, protected tags, and rules that decide who can push, merge, delete, or unprotect critical refs.
It matters because the repository is often the control point for software delivery. If an attacker can bypass review or alter protected branches, they may slip malicious code into builds, change release logic, or reach secrets used by CI/CD jobs. Strong repository protection reduces that risk with least-privilege permissions, required code review, status checks, signed commits, protected variables, and audit logs that help defenders spot policy failures quickly.