Thrilling news! Photocopies of eight folios of the Historia Passionis Domini, studied by Bernhard Bischoff and quoted by Kurt Aland in his New Testament Synopsis (p. 585) have been put online on the 7.10.23 by the MGH- Archive (München): MGH-Archiv K 195/19 n°6 (https://www.mgh-bibliothek.de/archiv/k/K_00195_19.htm)
This hyperlink is quoted on p. 312 in this forthcoming article: C. Clivaz, “Luke 22:43-44 and the Judeo-Christians”, REJ 182 (2023/3-4), p. 283-317.
One can now have access to images of f. 34v-36r, 54v-55r, 69v-70r, hoping that one day, the manuscript itself will be available again.