What is the idea here... support FA5 only with XF2.1+ or ship FA5 within VW? If the former, could you maybe adopt XF2's *.less template variables for the various FA icons rather than
directly embedding the icons? This might solve some of the FA4 vs FA5 complexities too, at least for the icons that exist in both versions under the same name.
In XF2.1, there is the templates "setup_fa.less" and "setup_fa4_variables.less", "core_fa.less". For XF 2.0, there is only "setup_fa_variables.less" and "core_fawidths.less"
Example: @fa-var-eye returns "\f06e". @fa-var-eye is a stock XF *.less variable.
This post from Chris D says they (XF) are licensed to
use FA5 Pro (emphasis mine):
https://xenforo.com/community/thread...1/post-1287489
I'm no lawyer, but if VW is 'hooking in' to an existing XenForo instance that ships with FA5 Pro on a particular site is it really a "new project"? And besides (again, not a lawyer) if VW isn't packing the FA5 fonts in the download package and just referencing XF's default font location in XF templates within XF system etc, why would it be VW's problem.
But anyway, if you wanted to cover yourself regardless, could the 'icon chooser' only display/suggest the FA4/FA5 free icons (the ones listed in setup_fa4_variables.less) but then have a method for manually typing in any fa css class? A bit like how XF2.1's new <xf:fa> template tag works textually via the "icon" attribute. Visually what I'm suggesting is something along the lines of XF2.1's emoji picker with the search box, except it could just override the icon selector with whatever text is entered rather. Emoji picker:
https://xenforo.com/community/thread...6/post-1289242
Something else to consider is FA5's different font weights. XF has automatic handling of the Solid/Regular/Light weights, e.g. <xf:fa icon="fa-user" /> = far/fal/fas depending on the active style's fontAwesomeWeight property. In other areas this is handled by fa_weight() in the CSS class, e.g. <i class="fa{{ fa_weight() }} fa-user"></i>. Details:
https://xenforo.com/community/thread...6/post-1292577).