Passpartout Slider is a Blender add-on from developer Costa that controls the active camera's passpartout alpha percentage. The whole tool is driven from the P key.
Holding P adjusts the passpartout alpha percentage, and tapping P toggles the effect off and on. The add-on requires no special permissions and is compatible with Blender 4.2 LTS and newer. It installs through Blender's standard extension process, either by dragging the file into Blender or installing it from disk, and is released under the GNU General Public License v3.0 or later.
Version 1.0.0 was published in July 2024 as the first implementation. Passpartout Slider ranks 287 in the blender_extensions library and has been downloaded more than fourteen thousand times. It holds a 5.0 rating across seven reviews, and the download itself is a compact 1.8 KB.