\documentclass{article} \usepackage{filecontents,fontspec} \begin{filecontents*}{juni.fea}...
Junicode 0.6.17 still didn't do it, only 0.7.0 and later does.
\documentclass[a4paper]{article} \usepackage{fontspec} \setmainfont{Junicode} \begin{document}...
\documentclass[a4paper]{article} \usepackage{fontspec} \setmainfont{Junicode} \begin{document}...