Editora 0.11.0. Archived, so links from that release keep working. Read the 0.18.5 page →
Edit: Remove Duplicate Lines
edit.removeDuplicateLines Remove duplicate lines from the selection (or the whole file), keeping each first occurrence.
How to run it
Open the command palette (M-x in the Emacs keymap) and search for Edit: Remove Duplicate Lines, then press Enter. It has no default keybinding, but you can bind one in Settings → Keymaps.