Why shouldn't there be indie books about subjects that are discussed frequently?
If something has been discussed millions of times, it means that the good information is scattered across several different sources and a lay person has no way of distinguishing between good and bad advice.
I've happily paid for indie books in the past few years from authors I trust because I want to read their perspective and information that they've curated.
Two I'll mention in particular:
Hello Web App by Tracy Osborn - This is a book about web design, which is discussed in millions of places, but Tracy's book gathers together high-quality information in a concise book.
Starting & Sustaining by Garrett Dimon - This is about running a small SaaS app. Another topic discussed in tons of places online, but Garrett is telling it from the context of his personal experience running a successful SaaS app for several years.
I plan to submit Splash of Code, which teaches brand new developers JavaScript by creating art. It's designed like the books I grew up on where you simply copy the authors code and then run it, plus it includes additional explanations.
I don't know any definition of "indy" that means "little public information".
Maybe a voting mechanism would float the good stuff to the top and maybe that's planned if the site catches on. Bravo to the builder.
If we take the same definition, as you did, and apply it to books written for developers, then I'm afraid an "indie book" in your context would be literally anything written by anyone on the internet.
My definition was that indie implied a sort of "unknown," as indie games often are.
Indie Books are books published outside of mainstream publishing. You're misrepresenting what Indie Books are with your own opinion of what you want to see on the site instead.
If the books are books for developers, then by now it's clear that they will be sold online. What effect does "mainstream publishing" have on publishing material on the internet? It's the internet. There is 0 meaningful difference if a book has mainstream publishing if both books can easily be listed on Amazon, Ebay, or anywhere else, because it's the internet.
"Indy books" should be about indie subjects. Topics that have little public information on them, but that can be interesting, valuable, or in some way beneficial. Yet all I see are books that hold the equivalent of 2010's Buzzfeed titles. Indie books could even be from indie authors, in the regard of creative writing (as my example above). But listing books on how to do something that's been discussed, and I don't think I'm exaggerating here, millions of times, doesn't seem like you're "helping developers find indie books."
I like the concept, but I'm not a fan of the execution. Of course, I'm a bit biased in the manner as I think anything beyond using the manual, Google, Discord/IRC, and forum, is generally a complete waste of time. Want to know anything? Manual > Google > Discord/IRC > forum post.