For openSUSE Leap 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/openSUSE_Leap_15.5/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1
For openSUSE Leap 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/openSUSE_Leap_15.4/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1
For SLE 15 SP5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/SLE_15_SP5/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1
For SLE 15 SP4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/SLE_15_SP4/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1
For SLE 15 SP3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/SLE_15_SP3/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1
For SLE 12 SP5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.5/SLE_12_SP5/LibreOffice:7.5.repo
zypper refresh
zypper install xmlsec1