In https://github.com/wikimedia/mediawiki/blob/master/resources/src/mediawiki.hlist/default.css several pseudo elements use content with characters that should translateable.
These should follow the example set in mediawiki.interface.helpers.styles and use ResourceLoaderLessVarFileModule::class with lessMessages option.
e.g.
.hlist dt:after {
content: ':';
}
.hlist dd:after,
.hlist li:after {
content: ' ·';
font-weight: bold;
}
/* Add parentheses around nested lists */
.hlist dd dd:first-child:before,
.hlist dd dt:first-child:before,
.hlist dd li:first-child:before,
.hlist dt dd:first-child:before,
.hlist dt dt:first-child:before,
.hlist dt li:first-child:before,
.hlist li dd:first-child:before,
.hlist li dt:first-child:before,
.hlist li li:first-child:before {
content: '(';
font-weight: normal;
}
.hlist dd dd:last-child:after,
.hlist dd dt:last-child:after,
.hlist dd li:last-child:after,
.hlist dt dd:last-child:after,
.hlist dt dt:last-child:after,
.hlist dt li:last-child:after,
.hlist li dd:last-child:after,
.hlist li dt:last-child:after,
.hlist li li:last-child:after {
content: ')';