As a user who frequently has hundreds of tabs, scrolling through all of them to get to where I want is cumbersome and annoying. Especially when the browser initially starts.
Upon pressing Cmd + K, the user will be prompted with a textbox in the center of the screen. There they will be able to type in quickly what tab they are looking for. The browser will have to save and index tab titles which I do not believe it does at the moment.
I can say this will make my workflow immensely better, being able to quickly get to where I need without scrolling and sometimes even having to load the web page because the browser doesn't cache the titles of tabs.
Some examples where I feel would be common
Fresh start of browser, hundreds of tabs. Have to get back to where you were working? Quick Cmd + K and they type in the page they're looking for and bam they're there. Also an option that should be implemented is whether or not upon entering a tab via a quick switcher your tab bar will be moved to where the searched tab is. Not just stuck wherever the user was before where they have to scroll through all tabs to get to where they are.
Another use case, imagine you're working on a project, have to research numerous things. Instead of having to go back and forth BAM Cmd K quick switcher and they search for what they need.
An example of the quick switcher in Discord before you type anything. It suggests mentions / channels you frequent. I believe in Orion something similar be done like showing pinned tabs or just tabs you visit frequently.
After typing what you want, you are shown a list that may match that you then either access with the arrow keys or click on the screen (uncommon)
An image of it on Slack (I do not use Slack personally, just an example from the web)
Additionally, Slack has optimized their Quick Switcher and explained how which may be helpful for the devs here.
