1a. And just in case the adobe-flashplugin package is missing, you may not have the "Canonical Parter" repo activated in Software & Updates / Software Sources, see Ubuntu's help page for 14.04 trusty or 16.04 xenial.
1a. And just in case the adobe-flashplugin package is missing, you may not have the "Canonical Parter" repo activated in Software & Updates / Software Sources, see Ubuntu's help page for 14.04 trusty or 16.04 xenial.