Man pages matching name xkbsaredirectsetvmods in section 3:

XkbSARedirectSetVMods.3.en	debian 10 / libx11-doc
XkbSARedirectSetVMods.3.en	debian 11 / libx11-doc
XkbSARedirectSetVMods.3.en	debian 12 / libx11-doc