A pipeline can be kicked off by more than "someone pushed code":
on:
push:
branches: [main]
pull_request:
schedule:
- cron: "0 3 * * *" # nightly at 3am UTC — e.g., a full regression suite
workflow_dispatch: # manual trigger, with optional inputs, from the CI UI
release:
types: [published]
Scheduled triggers are how teams run something too slow or too expensive to run on every single push — a full end-to-end suite, a dependency vulnerability scan, a nightly performance benchmark — without blocking every developer's feedback loop on it. workflow_dispatch (or the equivalent manual trigger on other platforms) is how a genuinely manual step, like "deploy this specific tag to production right now," stays inside the same auditable pipeline system instead of becoming an ad hoc script someone runs from their laptop.