PS : since copy of https://remixicon.com/icon/arrow-left-up-line (for example) are arrow-left-up-line : the string to set in this case must be arrow-left-up-lin and ri-not arrow-left-up-line

A way to have ri icon are
none ri-arrow-left-up-line
with font-awesome

Maybe solution

• remix : use ri-{TheValue}
• fontawesome : use fa fa-{TheValue}
• image : use image link
• free class : use {TheValue}

Current remix in core can move to free