Fair question. It might be internal jargon. Refers to making a go/no-go “call” on the quality/readiness of a new build.

e.g. A new release candidate is built and tested from a commit. Some tests fail and each test failure is blocking unless the product area owner (or test owner) attests that the issue is not a blocker (test flakiness, test environment specific issue, extremely low priority bug, etc). The build can release only when all test blockers are closed out.

Most build call processes I’ve seen burn more time investigating flaky tests than real issues and the person running build call (often the “release driver”) typically wastes significant time flogging people to close out the same flaky bugs from the last build. I strongly recommend not building one if you can avoid it.