Sorry that I couldn't log in here before, something was wrong with my password, but I have now fixed it. Hopefully I have provided helpful feedback in the GitHub site. I think I have fixed the first problem, the hard coding of the nova site should now be fixed. If you are using a package manager to install stellarsolver or if you are using Windows with embedded stellarsolver, there will be a delay to update it.
I think there were a couple of questions here I didn't address on the other site, so I will try to answer them now.
I am not sure what you mean by the internal solver can't blind solve, because that is one of the main things I worked really hard on last year during the pandemic, and one of the best features of StellarSolver is now that it can blind solves an image in less than a minute, often just a few seconds (depending on the image and computer of course). It manages this by doing several things that really can speed up solving such as parallel threads on multiple cores. Yes it can use a decent amount of energy and processing power, which is why you should only do a blind solve if it doesn't solve any other way. Even the raspberry pi can do it, but it isn't as fast as other computers.
I agree that under 1 second true blind solve on a Pi as you stated is not likely at this time. I typically use my laptop for solving images and controlling the session, where the PI is used for acquisition. My main computer solves images with scale and position information in about 0.3 seconds or so, the pi might take a few seconds (unless it is a pi 4). For blind solves it really really depends on the image. Here is an example of StellarSolver solving an image in less than 2 seconds on my main laptop. This is mostly a blind solve since the file is a JPEG, it has no idea about anything about the image. The only information it has is that it should use the parameters in the "ParallelSolving Small Scale" options profile. This profile does limit the scale to telescope sizes which makes it a bit faster, but if you don't limit the scale, it doesn't increase the time that much. Other images will have different solving times since blind solving is blind, but typically it is less than a minute. For a PI, the time estimates would be larger of course.
To answer the question of why 15 degrees, most users are using the internal solver or astrometry.net in some form and limiting the search 15 degrees does make a difference in those methods. 15 is typically the recommended parameter value. If your telescope is off by more than 15 degrees, there is a problem and you should be doing a blind solve and maybe check your equipment.