The command line

: in Normal or Visual mode, or Alt+; anywhere — including from a panel, so you never have to go back to the buffer first just to type :q.

/ and ? open the same bar for search.

:w	Save
:q	Close. With a panel open it closes the panel first — that is what you are looking at, and closing the buffer underneath it is the bigger, less recoverable action.
:q!	Close, discarding changes. Deliberately skips the panel rule: it is the escape hatch.
:42	Go to line 42
:s/from/to/	Substitute on this line. /g for every match, /i to ignore case.
:editor.replace-in-project	Replace across every file in the project, previewed first
:compile	Run build_command and show the output
:output	Show or hide the output panel
:config	Open your config file
:theme	List the themes; the current one is in [brackets]
:theme <name>	Apply it now, without writing anything
:theme save	Keep the applied theme
:<plugin command>	Run a command a plugin registered

An unrecognised name reports unknown command: <name> rather than doing nothing quietly — silence made a typo look like a command that ran.

Any command by name

Anything in Every command can also be typed here — :editor.find, :pane.close, :buffer.next — resolved exactly as a key binding resolves it, so a name means the same thing however you reach it.

Plugin command names work the same way.