I (well, my company) pays for https://onlinetools.com/ (USD 6 per month if you pay for a year upfront), which a found super-handy for (de-)prettifying and (de-)stringifying JSON. (It does a lot of other things too.)
Despite seeing code early in the series, didn't see any code that would actually put pixels on a screen, or even to write a static image into a file, at least not within the first 6 or 7 units. Somewhere around that point there is some reference to OpenGL, so presumably you could start to brighten patches of screen at that point?
Offering this as constructive criticism - the tutorials could be more engaging if the student could follow along and cause things to happen directly on the screen. It'd be awesome to organize the 1st unit as more than just confirming one has a compiler, to take it all the way to a kind of "hello, pixels".
I use an app called 'Alarmed' on my iPhone for this. It's got everything I need, in particular you can repeat items on a fixed period or 'x days from the time you actually manage to tick it off', which is great. It's free with a one-off IAP to unlock extra features (can't remember what they are - I paid it years ago).
Several years ago the company I work for offered a 'compressed working fortnight' option, where for nine days out of ten you work an extra 45 minutes a day and then get every other Friday off.
For me, this was an absolute game-changer in terms of quality of life. The majority of the company took it up and there's really been no issue in terms of overall productivity that I can see. If I ever change jobs, whether or not my new employer offers this will be a huge consideration for me.