krusader can't enter hidden archive

Hi all, thanks for your wonderful work on Ubuntu :)

The documentation at https://docs.kde.org/trunk5/en/extragear-utils/krusader/archives.html states that Krusader should support so-called hidden archives - zip files with extension different than .zip.

I have an apk file (Android application file), which is a zip file but with the .apk extension. Pressing right-arrow on the file does nothing - Krusader won't enter the file, even though it is a zip file.

Workaround is to rename the file to myapp.apk.zip; that will enable right arrow to work in Krusader and Krusader is now able to enter the archive and show its contents.

Krusader has probably a whitelist of extensions of such hidden archives, since it is able to enter, say, .jar files.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: krusader 2:2.5.0-2
ProcVersionSignature: Ubuntu 4.10.0-26.30-generic 4.10.17
Uname: Linux 4.10.0-26-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: KDE
Date: Mon Jul 3 09:58:30 2017
InstallationDate: Installed on 2016-09-05 (300 days ago)
InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
SourcePackage: krusader
UpgradeStatus: Upgraded to zesty on 2017-03-31 (93 days ago)