A new engine with few info about it. Here's below what i could find about the author Álvaro Begué:
"A Spanish computer checkers and computer chess programmer with expertise in machine learning and automated tuning, along with José Manuel Morán author of the Spanish Checkers program Torquemada and the chess program Ruy Lopez.
Since 2013, Álvaro is in the process to write a new chess engine. In November 2016, he published the open source tuning code RuyTune, an instance of a logistic regression performing limited-memory BFGS along with reverse-mode automatic differentiation and in June 2017 he published the open source engine RuyDos, co-authored by José Manuel Morán."
What surprises me is the strength which is around 2500 ELO easily. Besides, the build by Alexei works well so far. Unless i find out this is a derivative or clone (i don't think so, after reading more), it's really worth introducing into Rapidroid, which is what i'm doing now.
More about the engine can be read: HERE
In case of trouble downloading from your PC, use your mobile device or refer to THIS POST.
RuyDOS 1.0.3.ACH for arm7