At the moment, "Bruckner for guitar" is not a sensible search query and it may take some time to discover any activity in this area.
In 2011, French guitarist Noël Akchoté recorded arrangements of 10 Bruckner motets (among works of many other classical composers) on the acoustic guitar but, as far as I know, these arrangements, however they are evaluated, have not been published. My opinion is that acoustic guitar may be not the best kind of guitar for such music and I am not the only one who thinks that these performances are generally too fast and do not give justice to the character of Bruckner's sacred motets.
When I first heard of them, I was working on a set of 16 motets and other works for the classical guitar, which came out in Poland in 2016 as the first published arrangements of Bruckner’s music for the guitar. This publication was, however, premature and full of errors, for which I am mainly responsible.
A nice arrangement of Locus iste was more recently recorded by Bridget Mermikides. It is an excellent arrangement, beautifully performed; the only fault that I can find, enviously, is that the piece is transposed from C into A major.
Another Locus iste, by Mitsuhiro Iwasaki, this time in G major, is in my opinion less successful in terms of harmony and richness of sound.
There is also Steiermärker, a nice arrangement of a piano piece, by Stefan Niggl, who also offers a free glimpse into sheet music.
This shows that guitar arrangements of Bruckner's music are few and far between, and their quality varies. One important finding is that most arrangers (including myself) start from Locus iste.
It looks then like a virgin territory, which makes the present BRUCKNER FOR GUITAR project a real pioneer venture.