The documentation, included in the distribution says:
"If you downloaded this from MediaWiki.org, there should already be a 'geshi' directory in this folder. If there is, you can skip the next paragraph."
The documentation at [[mw:Extension:SyntaxHighlight GeSHi]] is clearer:
"Since r46666, we bundle Geshi into subversion. When downloading via the ExtensionDistributor or directly from SVN, there should already be a "geshi" directory inside your SyntaxHighlight_GeSHi directory. If this is the case then GeSHi is already installed."
No such folder exists, 4 files were unzipped: SyntaxHighlight_GeSHi.php, SyntaxHighlight_GeSHi.i18n.php, SyntaxHighlight_GeSHi.class.php, and README.
I downloaded the version for MW1.18 from the ExtensionDistributor. Either something is missing or the documentation is incorrect.
Version: unspecified
Severity: normal