I'm writing a book on PICO-8, and I'm one of the mods from the subreddit. I was wondering if you wouldn't mind letting me know where you found this out, or even just talk some PICO-8! I'm on Discord, but you email me so we can talk if you'd like! I see you are very active on this wiki, and it's been invaluable to me over the years, so thanks for all your hard work!
At some point zep tweeted out an early changelog for 0.1.12d and he listed it there. Several of us had been clamoring for these functions to be built-in, since a ton of us were wasting tokens implementing them over and over for apps. They should be live on the 0.1.12d release candidate the BBS is running, if you want to mess with them via uploaded cart.