Man pages matching name gst-launch-1.0 in section 1:

gst-launch-1.0.1.en	debian 10 / gstreamer1.0-tools
gst-launch-1.0.1.en	debian 11 / gstreamer1.0-tools
gst-launch-1.0.1.en	debian 12 / gstreamer1.0-tools
gst-launch-1.0.1.en	debian 13 / gstreamer1.0-tools