Punchlist is built to run without the mouse. These five carry a whole session; everything below them is there for when you need it. Ctrl is Cmd on a Mac.
These write plain Markdown into the task, so a copy or an export carries the formatting with it. Pressing the same pair again takes it back off. The task you are typing in shows its markers and every other row stays formatted; Settings → Formatting changes that, and turns these keys off.
A text field keeps ← and → for its own caret, so typing a repository name works normally. Up and down still walk out of it.