Could you be more precise about being "useless" and "for KDE3"?
Could you provide a screenshot to prove your point?
I've you tried, for instance, to run Kubuntu 12.10 live CD and check if is the same you see in Fedora 18? And what about Fedora 18 live?
I've debian GNU/Linux with KDE 4.8, and the packages:
libreoffice-kde
libreoffice-style-oxygen
and have you checked systemsettings->application appearance->gtk+ appearance?

(In reply to comment #1)
> Could you be more precise about being "useless" and "for KDE3"?

LibreOffice 4 has a package called "kde-integration". This package is not for KDE, but it's for KDE 3 *only*, because it depends from Qt 3/KDE 3 libs and it doesn't use Qt 4/KDE 4 libs. Oxygen integration works withouth this package.
Last KDE 3 version was relased more than 4 years ago; KDE 4.0 was relased 5 years ago.

I think that there are 2 option here:
1. If you think that KDE 3 support is important, rename this package to kde3-integration
2. Otherwise, drop it

> Could you provide a screenshot to prove your point?

Look at libk*.so.4 (take in mind that kdelibs4 are KDE 3 related and kdelibs5 are KDE 4 related) and at libqt*.so.3:

ldd /opt/lodev4.0/program/kdebe1.uno.so
        linux-vdso.so.1 =>  (0x00007fffdd1ff000)
        libkio.so.4 => not found
        libkdeui.so.4 => not found
        libkdecore.so.4 => not found
        libqt-mt.so.3 => not found
        libuno_cppu.so.3 => /opt/lodev4.0/program/../ure-link/lib/libuno_cppu.so.3 (0x00007f42c7781000)
        libuno_cppuhelpergcc3.so.3 => /opt/lodev4.0/program/../ure-link/lib/libuno_cppuhelpergcc3.so.3 (0x00007f42c74b4000)
        libuno_sal.so.3 => /opt/lodev4.0/program/../ure-link/lib/libuno_sal.so.3 (0x00007f42c7254000)
        libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f42c6f50000)
        libm.so.6 => /lib64/libm.so.6 (0x00007f42c6c4f000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f42c6a39000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f42c6680000)
        libuno_salhelpergcc3.so.3 => /opt/lodev4.0/program/../ure-link/lib/libuno_salhelpergcc3.so.3 (0x00007f42c6478000)
        libreg.so.3 => /opt/lodev4.0/program/../ure-link/lib/libreg.so.3 (0x00007f42c625c000)
        libxmlreader.so => /opt/lodev4.0/program/../ure-link/lib/libxmlreader.so (0x00007f42c604e000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f42c5e32000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00007f42c5c2e000)
        /lib64/ld-linux-x86-64.so.2 (0x000000335f400000)
        libstore.so.3 => /opt/lodev4.0/program/../ure-link/lib/libstore.so.3 (0x00007f42c5a0e000)

> I've you tried, for instance, to run Kubuntu 12.10 live CD and check if is
> the same you see in Fedora 18? And what about Fedora 18 live?
> I've debian GNU/Linux with KDE 4.8, and the packages:
> libreoffice-kde
> libreoffice-style-oxygen
> and have you checked systemsettings->application appearance->gtk+ appearance?

I haven't tried different distribution, but the output I get from ldd should be almost the same on every distribution with no KDE 3, because I'm using LibreOffice 4 beta 2 rpm packages.
KDE 4 integration works using gtk+ appearance (although it would be nice to have KDE 4 Native Widget Framework integration), but this bug it's mainly KDE 3 related.

If the Libreoffice 4 beta 2 deb packages are made like rpm ones, you could try to remove libreoffice-kde from your system (leaving libreoffice-style-oxygen installed) and see that nothing changes.

> I've installed LibreOffice 4 beta 2 from Linux x86_64 rpm packages on Fedora
> 18 KDE.
> 
> LibreOffice kde-integration is useless because it's for KDE 3: it should be
> removed (or maybe deprecated and renamed, like "kde3-integration", in order
> to avoid misunderstandings).

It looks to me like proper kde4 packages are built (for fc 19): 
http://koji.fedoraproject.org/koji/rpminfo?rpmID=3569094

If there is an issue at all, IMHO you should discuss it in fedora bugzilla since it looks like a packaging issue.

(In reply to comment #3)
> > I've installed LibreOffice 4 beta 2 from Linux x86_64 rpm packages on Fedora
> > 18 KDE.
> > 
> > LibreOffice kde-integration is useless because it's for KDE 3: it should be
> > removed (or maybe deprecated and renamed, like "kde3-integration", in order
> > to avoid misunderstandings).
> 
> It looks to me like proper kde4 packages are built (for fc 19): 
> http://koji.fedoraproject.org/koji/rpminfo?rpmID=3569094
> 
> If there is an issue at all, IMHO you should discuss it in fedora bugzilla
> since it looks like a packaging issue.

I'm talking about LibreOffice 4 beta 2 rpm "official" packages, not the Fedora ones. kde-integration.

This has kde-integration for KDE 3 only: http://download.documentfoundation.org/libreoffice/testing/4.0.0/rpm/x86_64/LibO-Dev_4.0.0.0.beta2_Linux_x86-64_install-rpm_en-US.tar.gz

This is for KDE 4: http://koji.fedoraproject.org/koji/rpminfo?rpmID=3569094

I'm reporting the bug here because this problem is not related with the Fedora package, but with the one distributed on LibreOffice.org website.

Indeed libkdecore.so.4 is for KDE3, so I agree with the reporter.
@comment2 the appearance is provided by KDE gtk integration, but I've found that removing the distro libreoffice-kde, LiBo looks the same but in file dialog you loose the "single click" when clicking on *folders*, so seems that gtk integration has a bug OR libreoffice-kde is providing something more.

@Francesco: thanks for your bug report and rather deep insight into issue. You are right, LibreOffice ships with support for KDE3. Which is not available in most of modern distributions.

I am marking this bug as duplicate of Bug 48611, because latter provides insightful comment by one of LibreOffice developers. To not scatter discussion, please post any additional comments there.

*** This bug has been marked as a duplicate of bug 48611 ***