Editora 0.20.0. Archived, so links from that release keep working. Read the 0.24.0 page →
View: Split Editor Group Right
view.splitEditorRight Move the current file into a new editor group to the right, so two files show side by side.
How to run it
Open the command palette (M-x in the Emacs keymap) and search for View: Split Editor Group Right, then press Enter. It has no default keybinding, but you can bind one in Settings → Keymaps.