The author, Mr. Andrew Grant at the time when chess engines using neural networks began to be released, quoted from CPW:
"(...) initially announced his withdrawal from Ethereal development with the release of Ethereal V12.75  and Ethereal 12.75 SF-NNUE"
"(...) Andrew Grant, however, opted for a different direction and announced the commercial release of Ethereal 13.00 (NNUE)".
Ethereal 14.00 is an open source chess engine under the GNU GPL 3 license, the source code of which is downloadable from the GitHub page, and it does not contain a neural network.
There is also Ethereal 14.00, which can be obtained by purchasing it from this page and it contains a neural network.
The free Ethereal 14.00 without a neural network is noticeably weaker than the commercial Ethereal 14.00 that contains a neural network.
I'm curious what you think about this approach. The comments section is at your disposal / I am also open to correspondence via email.
I make no secret of the fact that I like Ethereal's style of play; and when it was still possible to use it seamlessly on Macs, it was a frequent visitor to my chess arenas.
Unfortunately, recent commercial versions of Ethereal do not support other devices besides Windows and Linux. This is a pity, as there are many chess enthusiasts interested in the Ethereal chess engine on for eg. their Mac (about devices using ARM processors I won't even mention).
In my opinion, if one is willing and able to afford it, then it is worth supporting good commercial chess engines and software. There are fewer and fewer of them and they are less and less real competition for open source software. I do it myself and enjoy every new release. I wish I could write the same about the Ethereal chess engine.
Thank you very much to the author of the Ethereal chess engine for sharing the source code, and...
Feel free to download Ethereal 14.00 (does not include neural network).
Android – Compiled by Archimedes
Linux arm64 & x64 – Compiled by Darius
Windows x64 – Compiled by Darius
In the Files area you will find free chess engines for download.