The D3D11 back-end uses a code generator to initialize D3D11 format info. The generator is gen_texture_format_table.py and uses data stored in texture_format_data.json and texture_format_map.json. The “format map” maps from a GLES front-end format to the ANGLE format which represents the format we use in D3D11. The “format data” indicates which DXGI formats we use to represent an ANGLE format in the D3D11 back-end.
Note that the “format data” can also encode support for fallback formats. The supportTest attribute indicates a runtime check we can use to determine if we should use the fallbackFormat instead of the default format.