When the snap build is running on Jenkins, error appears Failed to find extension 'gnome-3-28': a extension by that name does not exist. Check the extension name and try again.
The dockerfile specifies the installation of the extension. Please help me how to install the gnome-3-28 extension correctly, if this is the problem. Or should I ask this question on the Jenkins forum?
Hi and welcome 
What version of snapcraft are you running inside your jenkins builds? or where are you acquiring it from?
Install in dockerfile using apt-get install snapd snapcraft.
At the same time, everything is running successfully locally from the terminal, the problem is in the build via Jenkins with the missing gnome-3-28 extension.
The version of Snapcraft you can get from the apt repositories is out of date. You should use the version that is installed as a Snap package. This will be an issue with dockerfile usage, however, so you might want to consider the Docker Image with Snapcraft already installed.
Thanks!