As root:
zypper ar -f https://download.opensuse.org/repositories/network:/im:/signal/openSUSE_Leap_15.3/ signal
When you install something, you have on the first time trust the key for the Repo always
zypper in signal-desktop
Loading repository data...
Reading installed packages...
Resolving package dependencies...
The following 13 NEW packages are going to be installed:
libIex-3_1-30 libIlmThread-3_1-30 libImath-3_1-29 libMagickCore-7_Q16HDRI10 libmatio9 libOpenEXR-3_1-30
libopenslide0 libraw20 libvips42 libvpx7 nodejs-electron signal-desktop vips-modules-8.12
13 new packages to install.
Overall download size: 148,3 MiB. Already cached: 0 B. After the operation, additional 538,8 MiB will be
used.
Continue? [y/n/v/...? shows all options] (y):
Retrieving package libmatio9-1.5.17-bp153.1.16.x86_64 (1/13), 109,0 KiB (431,2 KiB unpacked)
Retrieving: libmatio9-1.5.17-bp153.1.16.x86_64.rpm .................................................[done]
Retrieving package libopenslide0-3.4.1-bp153.1.18.x86_64 (2/13), 93,0 KiB (229,1 KiB unpacked)
Retrieving: libopenslide0-3.4.1-bp153.1.18.x86_64.rpm ..............................................[done]
Retrieving package libIex-3_1-30-3.1.4-lp153.91.1.x86_64 (3/13), 102,5 KiB (519,5 KiB unpacked)
Retrieving: libIex-3_1-30-3.1.4-lp153.91.1.x86_64.rpm ..............................................[done]
Retrieving package libImath-3_1-29-3.1.3-lp153.12.2.x86_64 (4/13), 41,1 KiB (321,9 KiB unpacked)
Retrieving: libImath-3_1-29-3.1.3-lp153.12.2.x86_64.rpm ............................................[done]
Retrieving package libraw20-0.20.2-lp153.156.1.x86_64 (5/13), 315,1 KiB ( 2,1 MiB unpacked)
Retrieving: libraw20-0.20.2-lp153.156.1.x86_64.rpm .................................................[done]
Retrieving package libvpx7-1.11.0-lp153.131.1.x86_64 (6/13), 857,4 KiB ( 2,5 MiB unpacked)
Retrieving: libvpx7-1.11.0-lp153.131.1.x86_64.rpm ......................................[done (2,5 KiB/s)]
Retrieving package nodejs-electron-17.1.2-lp153.58.4.x86_64 (7/13), 82,0 MiB (289,0 MiB unpacked)
Retrieving: nodejs-electron-17.1.2-lp153.58.4.x86_64.rpm ...............................[done (5,0 MiB/s)]
Retrieving package libIlmThread-3_1-30-3.1.4-lp153.91.1.x86_64 (8/13), 30,8 KiB ( 31,5 KiB unpacked)
Retrieving: libIlmThread-3_1-30-3.1.4-lp153.91.1.x86_64.rpm ........................................[done]
Retrieving package libOpenEXR-3_1-30-3.1.4-lp153.91.1.x86_64 (9/13), 583,9 KiB ( 2,9 MiB unpacked)
Retrieving: libOpenEXR-3_1-30-3.1.4-lp153.91.1.x86_64.rpm ..............................[done (2,5 KiB/s)]
Retrieving package libMagickCore-7_Q16HDRI10-7.1.0.27-lp153.603.1.x86_64
(10/13), 1,8 MiB ( 6,1 MiB unpacked)
Retrieving: libMagickCore-7_Q16HDRI10-7.1.0.27-lp153.603.1.x86_64.rpm ..................[done (1,9 MiB/s)]
Retrieving package libvips42-8.12.1-lp153.85.1.x86_64 (11/13), 1,1 MiB ( 3,0 MiB unpacked)
Retrieving: libvips42-8.12.1-lp153.85.1.x86_64.rpm .....................................[done (3,4 MiB/s)]
Retrieving package vips-modules-8.12-8.12.1-lp153.85.1.x86_64 (12/13), 67,4 KiB (149,8 KiB unpacked)
Retrieving: vips-modules-8.12-8.12.1-lp153.85.1.x86_64.rpm .........................................[done]
Retrieving package signal-desktop-5.36.0-lp153.1.1.x86_64 (13/13), 61,1 MiB (231,5 MiB unpacked)
Retrieving: signal-desktop-5.36.0-lp153.1.1.x86_64.rpm .................................[done (4,4 MiB/s)]
Checking for file conflicts: .......................................................................[done]
( 1/13) Installing: libmatio9-1.5.17-bp153.1.16.x86_64 .............................................[done]
( 2/13) Installing: libopenslide0-3.4.1-bp153.1.18.x86_64 ..........................................[done]
( 3/13) Installing: libIex-3_1-30-3.1.4-lp153.91.1.x86_64 ..........................................[done]
( 4/13) Installing: libImath-3_1-29-3.1.3-lp153.12.2.x86_64 ........................................[done]
( 5/13) Installing: libraw20-0.20.2-lp153.156.1.x86_64 .............................................[done]
( 6/13) Installing: libvpx7-1.11.0-lp153.131.1.x86_64 ..............................................[done]
( 7/13) Installing: nodejs-electron-17.1.2-lp153.58.4.x86_64 .......................................[done]
( 8/13) Installing: libIlmThread-3_1-30-3.1.4-lp153.91.1.x86_64 ....................................[done]
( 9/13) Installing: libOpenEXR-3_1-30-3.1.4-lp153.91.1.x86_64 ......................................[done]
(10/13) Installing: libMagickCore-7_Q16HDRI10-7.1.0.27-lp153.603.1.x86_64 ..........................[done]
(11/13) Installing: libvips42-8.12.1-lp153.85.1.x86_64 .............................................[done]
(12/13) Installing: vips-modules-8.12-8.12.1-lp153.85.1.x86_64 .....................................[done]
(13/13) Installing: signal-desktop-5.36.0-lp153.1.1.x86_64 .........................................[done]
as User:
signal-desktop