Find the text to convert to Markdown (e.g., in another browser tab)
Copy it to the clipboard (Ctrl+C, or ⌘+C on Mac)
Paste it into this window (Ctrl+V, or ⌘+V on Mac)
The converted Markdown will appear!
The conversion is carried out by to-markdown, a Markdown converter written in JavaScript and running locally in the browser. This version is based on clipboard2markdown by Euan Goddard.