§ 266 When offense is bailable.

If you're arrested and the judge decides you can be released on bail while you wait for your case to be handled, the judge has to write that down on the arrest paperwork. The judge adds a note saying something like "I have admitted him to bail, to answer, by the undertaking hereto annexed." This basically confirms that bail was granted and that you signed an agreement (called an undertaking) promising to show up for your court dates.

This note gets attached to the same paperwork the judge already filled out earlier in the process. It creates a clear record that bail was set and accepted, so there's no confusion later about whether you were released on bail or held in custody. This paperwork trail protects both you and the court by documenting exactly what happened with your case.