In the lean tradition, lead time runs from idea to delivered value; DORA narrows it to from commit to production, because that part is almost entirely governed by the delivery flow: build times, review, test environments, approvals and release windows. The difference between teams that deploy the same day and teams that wait for weeks rarely sits in the writing of code but in the time the code sits still.
Shortening lead time is most of what delivery engineering is: trunk-based development, small changes, automated tests and a pipeline that doesn't need someone to press a button. The most visible part — waiting for the build — is what the build wait calculator puts a number on.