\ProvidesExplFile{example.tex}{2024-04-09}{1.0.0}{An example file}
\tl_new:N
  \g_example_tl
\tl_gset:Nn
  \g_example_tl
  { Hello,~ }
\tl_gput_right:Nn
  \g_example_tl
  { world! }
\ExplSyntaxOff
\tl_use:N  % error on this line
  \g_example_tl  % error on this line