Verticality Vertex Measure
How To Install
First, click 'Edit' on the top menu, then 'Preferences', and select 'Add-ons' on the left. Click 'Install' in the top right corner, choose the 'Verticality Vertex Measure' script from the file selector, and then click the 'Install' button at the bottom right.
After installation, you will see the plugin appear in the list. Click the triangle on the left to see more details. Don't forget to activate the plugin by checking the checkbox.
Open the panel on the right side of the 3D view to see the plugin menu.