Trope Trainer is a software package for working with Hebrew cantillation (trope). You can use it to view, listen to, or print the weekly Torah reading (or parts thereof), weekday readings, holiday readings, etc. As the "trainer" in the name implies, one of its purposes is to teach the cantillation system -- or, I should say, systems, because there are regional and other variations.
I didn't use it for that because I already know (my community's) cantillation system; while occasional curiosity might lead me to ask it "hey, how does the Lithuanian tradition chant this?", in practice I haven't. No, what I use Trope Trainer for is to print legible copies with the vowel markers and trope markers. These are useful for practicing and, when I know in advance so I can print it, for checking the reader during the service, because the scroll used for readings does not have vowels and trope marks. (There is always somebody following along during a Torah reading to correct the reader in case of mistakes.)
Back in August, somebody in my minyan asked me to be his checker the following Shabbat, so I launched the program to print a copy. But the program was stuck at "checking for updates", a state that had previously passed so quickly that I wasn't used to seeing it. If I cancelled, the program crashed. Repeatedly. A little digging revealed the probable cause: the company went out of business and their domain isn't there any more. Presumably the software is checking a now-dead URL and the programmers didn't handle failures. (There are other reasons the service might not be available, so this isn't just "didn't consider the company might die".)
I asked on Judaism Codidact about alternatives and people made some useful suggestions, but cutting/pasting text from elsewhere into Google Docs, while it works, is inelegant and also produced some formatting glitches.
My too-clever hind-brain said to me: hey, if the software is trying to reach a particular URL, you could intercept it (edit the hosts file) and then try to figure out what to send back (though you would have to learn how to write a web service, but hey, that seems doable?). This is the point where people who know more than I do say things like "Wireshark", which I installed but couldn't figure out how to use to identify what it was trying to contact. I asked for clues on Power Users, where someone helpfully asked what the program does if it's not connected to the Internet. Bingo -- the programmers didn't anticipate "our site is down" but did anticipate "not connected", presumably because some in the observant world do avoid the Internet.
But this required pulling the network cable, because apparently there's no way on a Mac to say "yes I know you have an Ethernet cable right there, but please humor me and ignore it". I don't want to pull the cable every time I need Trope Trainer; that's too coarse a solution. This is a job for a firewall, but the firewall built into Mac OS only intercepts inbound traffic (or responses to it). I needed to block initiation of outbound traffic from one specific application. Power Users led me to Lulu, which does the job nicely -- and seems useful anyway as an additional layer of defense against malware that phones home (which is most of it, right?). Also, I don't mind having to authorize Java updates and stuff like that.
I didn't want to rely on a hobbled Trope Trainer forever, so I started working my way through the weekly portions, saving PDFs. In the future I can print from those, after all, and can let the software die.
And then I moved to a new machine that can't run the software, which dealt the final blow to Trope Trainer. But going through all this did lead me to that useful firewall, so I don't mind.
And meanwhile, my question on Judaism Codidact has gotten a new answer with a different way to produce nice large copies of what I need. Nice!