3D Navigation is a Blender add-on that places 3D Viewport navigation controls in the Sidebar. You'll find it under View3D → Sidebar → View tab, where its panel lets you move around the viewport without relying on the numpad.
The extension began as one of Blender 4.1's bundled add-ons and is now offered on its own with limited support. It was originally created by Demohero and uriel. Version 1.3.0 adds custom view directions and a new UI.
3D Navigation is compatible with Blender 4.2 LTS and newer and is distributed under the GNU General Public License v3.0 or later. It requires no special permissions and, at 3.2 KB, installs by dragging the extension into Blender or using Install from Disk. With more than 45,000 downloads to date, it remains a small, self-contained panel rather than a heavyweight tool.