I'm working a lot with GDAL VRT raster layers in QGIS 3.14, often changing the file content while viewing the rasters in map canvas. When I zoom or refresh the canvas in QGIS 2.18, all modified VRT raster layers are refreshed as well. In QGIS 3.14 it looks like VRT layers are cached. I can refresh the virtual raster layers only with the help of the indispensible "changeDataSource" plugin.
What do I need to refresh a VRT layer with Python?