Detached plugin handling changes in 2.178 could cause problems for some custom Jenkins home packaging schemes that use improper filenames.
These cases are now at least warned about, and in some cases transparently handled.
(issue 55582)
Change the presentation of boolean (checkbox) options for most options on configuration forms.
(issue 55787)
Developer: Make the XMLUtils class with utility methods related to safe XML processing available to plugins.
(pull 4032)