Ships a 'cogl' third party plugin that is broken
The SDK ships a high rank cogl plugin (coglsink element) that broken. The plugin spits a lot of criticals assersion in every way of usage. Because it's high rank, it break automatic selection of the display element.
To reproduce:
flatpak run --command=/bin/bash --share=network --socket=pulseaudio --socket=wayland org.gnome.Sdk/x86_64/3.28
gst-inspect-1.0 cogl
. . .
(gst-inspect-1.0:7): GLib-CRITICAL **: 12:16:29.864: g_source_get_priority: assertion 'source != NULL' failed
. . .
gst-play-1.0 https://upload.wikimedia.org/wikipedia/commons/transcoded/c/c0/Big_Buck_Bunny_4K.webm/Big_Buck_Bunny_4K.webm.360p.vp9.webm
. . .
(gst-play-1.0:3): GStreamer-CRITICAL **: 12:18:59.947: gst_caps_intersect_full: assertion 'GST_IS_CAPS (caps1)' failed
. . .
streaming stopped, reason not-negotiated (-4)
This can be worked around explicitly passing the videosink, with --videosink=glimagesink or --videosink=waylandsink. I think such a low quality third party plugin should be low rank or simply not included into the SDK.