From which commit or branch will you create a new branch?

Usually from the latest stable version (main or master). Depending on the project, this could be:

• The latest commit of the main branch: For developing new features, bug fixes, or experiments.
• A specific release tag: For making changes to a particular released version.
• Another branch: For example, for developing a sub-feature from an already ongoing major feature.

The choice depends on the purpose of the new branch and the project's branching strategy.