Ogre Jailbreaker — ruling 1

Defender only matters when Ogre Jailbreaker could be declared as an attacking creature. If Ogre Jailbreaker is already attacking, losing control of your only Gate won't cause Ogre Jailbreaker to leave combat.

Ogre Jailbreaker : règles, fonctionnement et interactions (MTG)

Ogre Jailbreaker is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Defender This creature can attack as though it didn't have defender as long as you control a Gate.

How it works : Ogre Jailbreaker

Original English text — Wizards of the Coast / Scryfall

#1March 14, 2017· Wizards of the Coast
Defender only matters when Ogre Jailbreaker could be declared as an attacking creature. If Ogre Jailbreaker is already attacking, losing control of your only Gate won't cause Ogre Jailbreaker to leave combat.
No other card is named in this ruling.