Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
AI TechDocKnowledge

Glossary · Automation software engineering and architecture

Main branch

Also known as: Mainline, Trunk, Master branch

German: Hauptbranch

In version control, the main branch is the long-lived branch of a repository that holds the integrated, reference state of the code from which releases and feature branches are derived.

  • Software engineering

In one sentence

The main branch is the long-lived repository branch holding the integrated reference state of the code from which releases are built.

Example

The PLC project team merges each reviewed feature branch into the main branch, and the nightly build creates the test image for the conveyor line from it.

How it applies

  • Engineering: Teams protect the main branch with rules: changes arrive only through a Pull request with review and a passing Test pipeline. This keeps the main branch buildable at all times.
  • Release management: A Software release is tagged on the main branch or on a release branch cut from it, so every shipped version can be traced back to one commit.
  • Documentation: Documentation sources that live in the same repository follow the same rule. The documentation team should know which branch the published manual is built from and link each manual edition to a commit or tag, which supports the Configuration baseline.

Main branch vs. feature branch

The main branch is permanent and represents the agreed state of the product. A Feature branch is short-lived, isolates one change and is deleted after its Merge. Naming varies: older repositories call the main branch master or trunk.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on common version control practice (Git)

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

Seen a mistake? Send us a note!