Quite a while back
draw_render_target_debug() was changed to use
Texture::is_render_target() to decide whether to display a texture (rather than the render targets being stored in a separate collection than other texture cache textures). However,
is_render_target() just checks whether the texture can be rendered to (due to having an FBO), which includes most textures in the texture cache, not just ones we refer to as "render targets".
More recently, in bug 1711486, we attempted to ensure that
gfx.webrender.debug.texture-cache did not show picture cache tiles. To do this we filtered the textures in
do_debug_blit() to include only those with the flag
do_debug_blit() is shared by both
draw_render_target_debug(), and render targets do not have that flag set.
The consequence of both of these changes is that
draw_render_target_debug() draws texture cache atlases, but doesn't actually display our render targets.
To fix this, we can filter by
draw_texture_cache_debug() rather than
do_debug_blit(). And in
draw_render_target_debug() we can filter by the newly added
TextureCacheCategory::RenderTarget, rather than