Re: jar files won't open in emacs 27.1 on debian 11.6 "bullseye"

[Steinar Bang]

>>>>> Yuri Khan <yuri.v.khan@gmail.com>:

> ZIP archives are not defined by the magic number in the starting
> bytes. It is valid to prepend anything to a ZIP archive. This is used
> by self-extracting archives where the starting part is an executable.

> The defining part of a ZIP archive is the End of central directory
> record, magic number PK\x05\x06; it is optionally preceded by Zip64
> extensions (PK\x06\x07 and PK\x06\x06), further preceded by Central
> directory headers (PK\x01\x02). These are sufficient for displaying a
> directory listing of the archive.

> PK\x03\x04 is the signature for Local file header, which marks the
> start of an actual compressed file’s data. So, indeed, a plain
> unadorned non-empty ZIP archive will start with PK\x03\x04, but it is
> not the magic number for ZIP archives and a conforming archive
> processor should not scan specifically for that, at least until it is
> asked to actually extract enclosed files.

Not saying it should. 

Just saying it looks like the code doesn't find what it looks for in
that file and that's why it gets the Args out of range error.