I asked Where does Master Overwatch get its data from?, which was incorrectly closed as off topic. The mods assumed it was about game design or development, but Master Overwatch is not a game designer or developer. They do not make games. They are an Overwatch stats website.
I then asked this question and deleted all references to Blizzard, development, and APIs to avoid confusion. It was closed as a duplicate of the first.
For reference, here is the on-topic FAQ.
A commenter suggest I appeal here, so here I am. (My typing is terse because I'm on a phone.)