[lltx] Alternate (and Annotation) option under fontspec does not work

[Dohyun Kim]

Hi,

\unless\ifdefined\ProvidesPackage
\input luaotfload.sty
\font\1="[Junicode-Regular]:+salt=2" \1
kG
\expandafter\bye
\fi
\documentclass{article}
\usepackage{fontspec}
\begin{document}
\fontspec[Alternate=1,ExternalLocation]{Junicode-Regular}
kG
\end{document}

Upon compiling with luatex, the code above works flawlessly.
However, compiling with lualatex gives me some warnings like this:

 fontspec warning: OpenType feature 'Alternate=1' (+salt=2) not available
(fontspec)  for font 'Junicode-Regular',
(fontspec)  with script 'Latin', and language 'Default'.

And as a result GSUB does not work.
The Annotation (nalt) option has similar issue.

Best,
-- 
Dohyun Kim
College of Law, Dongguk University
Seoul, Republic of Korea