Relating to appeals from orders granting or denying a plea to the jurisdiction by a governmental unit in certain circumstances.

HB 3647 clarifies when appeals can be taken from court decisions regarding government entities' challenges to a court's authority (pleas to the jurisdiction) in specific cases. The bill adds an exception to existing appeal rules, stating that appeals do not apply to orders granting or denying such pleas when the case involves a mandamus action (where someone seeks to force a government official to perform a duty). This directly affects government units (like cities or counties) and individuals or organizations suing them in mandamus cases. The change streamlines the legal process by removing the right to appeal certain jurisdictional decisions in these specific proceedings.