Edit Linked Library is a Blender add-on from JasonvanGumster that allows editing of objects, collections, and node groups linked from external libraries. It was originally part of Blender 4.1's bundled add-ons and is now offered as it is, with limited support.
You reach its controls from a few places in Blender: File → External Data, the Item tab in the View3D Sidebar, and the Node tab in the Node Editor Sidebar. The add-on requires no special permissions and is released under the GNU General Public License v2.0 or later.
Version 0.9.2 is compatible with Blender 4.2 LTS and newer. It was published in May 2024 and carries no changelog for this release. The original authors are Jason van Gumster (Fweeb), Bassam Kurdali, Pablo Vazquez, and Rainer Trummer.