In Bień, Janusz S. “Towards an Inventory of Old Print Characters: Ungler’s Rubricella , a Case Study.” TUGboat 44, no. 3 (2023): 364–75. https://doi.org/10.47397/tb/44-3/tb138bien-rubricella (see also the errata) I wrote
Almost all the resources discussed here will be available, after additional verification, in a public repository at https://github.com/jsbien/Rubricella
Unfortunately there was no additional verification, the resources are available "as is".
Please do not hesitate to open issues and start discussions using the repository facilities.