Non-ASCII © in Copyright String

[pauldhunt]

Error reported from validation:
Cff ascii strings: The following CFF TopDict strings are not in the ASCII range: - Copyright: © 2023 Adobe. All rights reserved, with Reserved Font Name 'Source'. [code: cff-string-not-in-ascii-range

[frankrolf]

What I found out about this is that the CFF TopDict string is equivalent to the copyright field in the fontinfo.plist of your UFO file:
adobe-type-tools/afdko#1767 (comment)

In other words, there is no need to escape the copyright in the nameIDs.fea file. Instead, it would make sense to keep the UFO copyright string to ASCII only.