Am Do., 5. Nov. 2020 um 19:41 Uhr schrieb Thiede, Christoph
<Christoph.Thiede at student.hpi.uni-potsdam.de>:
>
> Good catch! That's clearly a bug IMO. #extension should use #copyAfterLast: rather than #copyAfter:.
>

Pharo has it like this as well, so it is also an unnecessary incompatibility:

extension
    "Return the extension of path basename i.e., /foo/gloops.taz
extension is 'taz'"
    ^ self basename copyAfterLast: self extensionDelimiter

>
> On the other, FSReferenceTest >> #testBaseAndExtension explicitly defines a test where it says:
>
> "Note that the extension of a complex extension starts from the first period up until the end"
>

The original author might either have just documented that status quo,
or thought of something like .tar.gz. Again Pharo has changed this to
"Note that the extension of a complex extension starts after the last
extension delimiter".