As of 2020-12-10 these are the X11 packages used by the debiant2 Wine TestBot VM, and the cw-gtx560 and cw-rx460 machines:
libx11_1.7.0-0wtb1.diff.gz
libx11_1.7.0.orig.tar.gz
To install these packages on Debian Testing you will also need a recent x11proto-dev package.
libx11-6_1.7.0-0wtb1_amd64.deb
libx11-6_1.7.0-0wtb1_i386.deb
libx11-data_1.7.0-0wtb1_all.deb
libx11-dev_1.7.0-0wtb1_amd64.deb
libx11-dev_1.7.0-0wtb1_i386.deb
libx11-xcb-dev_1.7.0-0wtb1_amd64.deb
libx11-xcb-dev_1.7.0-0wtb1_i386.deb
libx11-xcb1_1.7.0-0wtb1_amd64.deb
libx11-xcb1_1.7.0-0wtb1_i386.deb