A letterhead saved by Illustrator 28 without PDF compatibility wouldn't
open: "its editing data can't be read (it ends inside a layer)". Its
layer starts with a /ForeignObject (non-native art: the content of a
placed PDF), whose /Data entry is the PDF as ASCII85 in comment lines.
ASCII85 includes `_`, so about one line in 85 starts with `%_`, which
the lexer reads as hidden tokens; a `(` in such a line opened a string
that swallowed the dictionary's end, the rest of the art and the
layer's LB.
The reader now skips to the data's `~>` after `/Data ,` in a
/ForeignObject, as it already did for a /Binary dictionary's ASCII85,
and leaves the non-native art out with a note (nothing draws its PDF
from the editing data yet).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017ZwZjADUZP4VzvrFGpiZch