speedbar-supported-extension-expressions

speedbar-supported-extension-expressions is a variable defined in `speedbar.el'.
Its value is

("\\.vhdl?\\'" ".adb.dg" ".ads.dg" ".adb" ".ads" ".org" ".pro" ".[ch]\\(\\+\\+\\|pp\\|c\\|h\\|xx\\)?" ".tex\\(i\\(nfo\\)?\\)?" ".el" ".emacs" ".l" ".lsp" ".p" ".java" ".js" ".f\\(90\\|77\\|or\\)?" ".ad[abs]" ".p[lm]" ".tcl" ".m" ".scm" ".pm" ".py" ".g" ".s?html" ".ma?k" "[Mm]akefile\\(\\.in\\)?")

Original value was

(".[ch]\\(\\+\\+\\|pp\\|c\\|h\\|xx\\)?" ".tex\\(i\\(nfo\\)?\\)?" ".el" ".emacs" ".l" ".lsp" ".p" ".java" ".js" ".f\\(90\\|77\\|or\\)?" ".ad[abs]" ".p[lm]" ".tcl" ".m" ".scm" ".pm" ".py" ".g" ".s?html" ".ma?k" "[Mm]akefile\\(\\.in\\)?")

Documentation:
List of regular expressions which will match files supported by tagging.
Do not prefix the `.' char with a double \ to quote it, as the period
will be stripped by a simplified optimizer when compiled into a
singular expression. This variable will be turned into
`speedbar-file-regexp' for use with speedbar. You should use the
function `speedbar-add-supported-extension' to add a new extension at
runtime, or use the configuration dialog to set it in your init file.
If you add an extension to this list, and it does not appear, you may
need to also modify `completion-ignored-extension' which will also help
file completion.

You can customize this variable.