Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
application()
application(signal-desktop-tray.desktop)
application(signal-desktop.desktop)
libffmpeg.so()(64bit)
libnode.so()(64bit)
signal-desktop
signal-desktop(x86-32)

Requires :

/bin/sh
ld-linux-x86-64.so.2()(64bit)
ld-linux-x86-64.so.2(GLIBC_2.2.5)(64bit)
ld-linux-x86-64.so.2(GLIBC_2.3)(64bit)
libX11-xcb.so.1()(64bit)
libX11.so.6()(64bit)
libXcomposite.so.1()(64bit)
libXcursor.so.1()(64bit)
libXdamage.so.1()(64bit)
libXext.so.6()(64bit)
libXfixes.so.3()(64bit)
libXi.so.6()(64bit)
libXrandr.so.2()(64bit)
libXrender.so.1()(64bit)
libXss.so.1()(64bit)
libXtst.so.6()(64bit)
libasound.so.2()(64bit)
libasound.so.2(ALSA_0.9)(64bit)
libatk-1.0.so.0()(64bit)
libatk-bridge-2.0.so.0()(64bit)
libc.so.6()(64bit)
libc.so.6(GLIBC_2.11)(64bit)
libc.so.6(GLIBC_2.14)(64bit)
libc.so.6(GLIBC_2.15)(64bit)
libc.so.6(GLIBC_2.17)(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.3)(64bit)
libc.so.6(GLIBC_2.3.2)(64bit)
libc.so.6(GLIBC_2.3.3)(64bit)
libc.so.6(GLIBC_2.3.4)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libc.so.6(GLIBC_2.6)(64bit)
libc.so.6(GLIBC_2.7)(64bit)
libc.so.6(GLIBC_2.9)(64bit)
libcairo.so.2()(64bit)
libcups.so.2()(64bit)
libdbus-1.so.3()(64bit)
libdbus-1.so.3(LIBDBUS_1_3)(64bit)
libdl.so.2()(64bit)
libdl.so.2(GLIBC_2.2.5)(64bit)
libexpat.so.1()(64bit)
libffmpeg.so()(64bit)
libfontconfig.so.1()(64bit)
libgcc_s.so.1()(64bit)
libgcc_s.so.1(GCC_3.0)(64bit)
libgdk-3.so.0()(64bit)
libgdk_pixbuf-2.0.so.0()(64bit)
libgio-2.0.so.0()(64bit)
libglib-2.0.so.0()(64bit)
libgobject-2.0.so.0()(64bit)
libgtk-3.so.0()(64bit)
libm.so.6()(64bit)
libm.so.6(GLIBC_2.2.5)(64bit)
libnode.so()(64bit)
libnspr4.so()(64bit)
libnss3.so()(64bit)
libnss3.so(NSS_3.10)(64bit)
libnss3.so(NSS_3.11)(64bit)
libnss3.so(NSS_3.11.1)(64bit)
libnss3.so(NSS_3.12)(64bit)
libnss3.so(NSS_3.12.1)(64bit)
libnss3.so(NSS_3.12.3)(64bit)
libnss3.so(NSS_3.12.4)(64bit)
libnss3.so(NSS_3.2)(64bit)
libnss3.so(NSS_3.22)(64bit)
libnss3.so(NSS_3.3)(64bit)
libnss3.so(NSS_3.4)(64bit)
libnss3.so(NSS_3.5)(64bit)
libnss3.so(NSS_3.7)(64bit)
libnss3.so(NSS_3.8)(64bit)
libnss3.so(NSS_3.9.2)(64bit)
libnssutil3.so()(64bit)
libnssutil3.so(NSSUTIL_3.12)(64bit)
libnssutil3.so(NSSUTIL_3.12.3)(64bit)
libopenssl1_0_0
libpango-1.0.so.0()(64bit)
libpangocairo-1.0.so.0()(64bit)
libpthread.so.0()(64bit)
libpthread.so.0(GLIBC_2.2.5)(64bit)
libpthread.so.0(GLIBC_2.3.2)(64bit)
libpthread.so.0(GLIBC_2.3.3)(64bit)
librt.so.1()(64bit)
librt.so.1(GLIBC_2.2.5)(64bit)
libsmime3.so()(64bit)
libsmime3.so(NSS_3.10)(64bit)
libsmime3.so(NSS_3.2)(64bit)
libxcb.so.1()(64bit)
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rpmlib(PayloadIsXz) <= 5.2-1
rtld(GNU_HASH)

Content of RPM :
/usr/bin/signal-desktop
/usr/lib/signal-desktop
/usr/lib/signal-desktop/LICENSE.electron.txt
/usr/lib/signal-desktop/LICENSES.chromium.html
/usr/lib/signal-desktop/blink_image_resources_200_percent.pak
/usr/lib/signal-desktop/content_resources_200_percent.pak
/usr/lib/signal-desktop/content_shell.pak
/usr/lib/signal-desktop/icudtl.dat
/usr/lib/signal-desktop/libffmpeg.so
/usr/lib/signal-desktop/libnode.so
/usr/lib/signal-desktop/locales
/usr/lib/signal-desktop/locales/am.pak
/usr/lib/signal-desktop/locales/ar.pak
/usr/lib/signal-desktop/locales/bg.pak
/usr/lib/signal-desktop/locales/bn.pak
/usr/lib/signal-desktop/locales/ca.pak
/usr/lib/signal-desktop/locales/cs.pak
/usr/lib/signal-desktop/locales/da.pak
/usr/lib/signal-desktop/locales/de.pak
/usr/lib/signal-desktop/locales/el.pak
/usr/lib/signal-desktop/locales/en-GB.pak
/usr/lib/signal-desktop/locales/en-US.pak
/usr/lib/signal-desktop/locales/es-419.pak
/usr/lib/signal-desktop/locales/es.pak
/usr/lib/signal-desktop/locales/et.pak
/usr/lib/signal-desktop/locales/fa.pak
/usr/lib/signal-desktop/locales/fake-bidi.pak
/usr/lib/signal-desktop/locales/fi.pak
/usr/lib/signal-desktop/locales/fil.pak
/usr/lib/signal-desktop/locales/fr.pak
There is 80 files more in these RPM.