Rocker26a
Adventurer
It's not enshrined in their spellcasting mechanics because it's up to the DM to decide.
That's exactly the point though. There's no debate with your DM about whether a Gith can cast their Psionic Spells without components, for example. They can do it. It says so in the description of that ability, end of discussion. The argument is that Ranger's spellcasting would benefit from operating on a similar principle, without nagging your DM to allow it every time.