Essentially, you execute a shortcut which creates a new pop-up window (similar to macOS' Spotlight or the third-party app Alfred), that allows you to execute common commands. This could be switching to a tab, opening the history panel, toggling an extension, toggling reader view, et cetera. You type in the name of what you want to do and it does it. These are easier to learn than keyboard shortcuts and there can be far more of them.
The MVP would be a shortcut that opens a text box where the user can type in the name of a command as it appears in the menu bar and Orion executes it upon pressing enter (using arrow keys or the mouse to navigate if there are multiple matches). In other words, it would function very similar to the search bar in the 'help' section of the menu bar.
Nicer yet would be if it showed the most recent and/or most used commands by default, and if it included "submenus", for example you could type in 'history', search through your browsing history, then 'activate' whichever link you wanted into a new tab using enter.
Sidenote: A similar function exists in Vivaldi called "quick commands". It supports just about anything you can do in a browser. It would be nice to see something similar in Orion!