I was involved in another mmo's private server scene- what happened there was the source code for servers would get released after a server is taken down (whether by DMCA, or just pure infighting), then people build on top of that, then repeat. I would say a vast majority of the source code is not released to the public.
I built https://k.cote.sh which is a kanban board primarily for university students. I built it for myself as I'm currently doing the OMSCS program at Georgia Tech. I used to use Trello which was ok, and this semester I used just my personal calendar, which was also just ok.
The thing with the OMSCS program is that certain classes have different time zones for deadlines (from what I've seen it's either eastern or AoE/UTC-12). Then there's also the concept of "soft deadlines" for some classes. And most classes also release assignments/quizzes in batches on a particular date. Canvas (the LMS used at Georgia Tech) does expose an ICS you can subscribe to, but there's also a bunch of noise- "office hours", random OMSCS-specific announcements, etc.
I used Trello more extensively when I was in undergrad since an in-person program typically doesn't have the quirks above. Because I wanted to access it on mobile too, I deployed it. It's free and doesn't even require sign ups to use.
There's a standardized way to express what is happening in the game too- you'll often hear on the radio and television broadcasts the play that just happened using numbered positions on the field. 1 is pitcher, 2 is catcher, 3 is first baseman, 4 is second, 5 is third, 6 is shortstop, etc. so you'll hear something like "6-4-3 double play" which means the ball was fielded by the shortstop (6), thrown to the second baseman (4) for the first out, then to the first baseman (3) for the second one.
Makes it easy to visualize the game if listening on the radio.
Worked on this a few months ago but have finally gotten around to cleaning it up for open source release and setting up a pipeline to build the .dmg.
I built this for two reasons, (1) I (used to) work with people from many timezones, and (2) macOS used to include flags of the current keyboard set, which I liked, but was removed [1]. I liked seeing a flag on my menu bar so I combined my two wants to make this app. It was also an exercise to build a native macOS app.
It's lightweight (~36 MB of memory usage), free, and open source.
I'm not the author but my guess is that the API returns whether the number is registered with iMessage or not- like if you type in a number in a new text message it shows whether the message you're sending will be an iMessage or a text message. Don't think the author was spamming random numbers.