These are the grammar tokens which are introduced starting in 17.4. You use them when defining verbs.
This is a somewhat artificial example:
Colour is a kind of value. The colours are red, green and blue.
Understand "colour [a colour]" or "[a colour] shade" as "[tint]".
Tuning it to is an action applying to one thing and one colour.
Understand "tune [something] to [tint]" as tuning it to.
The laser is a thing. The player carries the laser.
say "You can tune a laser, but you can't tune [a noun]."
Report tuning the laser to:
instead say "You adjust the laser to [colour understood]."
The third input doesn’t work because just “green” doesn’t match the [tint] token.
(Really, given this action, players would only try the third input, and not either of the first two. That’s why I say it’s an artificial example.)