You can create a fake gstreamer0.10-plugins-good package using equivs:

1. install equivs

    sudo apt install equivs
   

2. generate a template control file

    equivs-contrl gstreamer0.10-plugins-good.control
   

3. fix the package name

    sed -i 's/<package name; defaults to equivs-dummy>/gstreamer0.10-plugins-good/g' gstreamer0.10-plugins-good.control
   

4. build the package

    equivs-build gstreamer0.10-plugins-good.control
   

5. install it

    sudo dpkg -i gstreamer0.10-plugins-good_1.0_all.deb
   

That should satisfy the opera package’s dependency.

You can’t make apt ignore dependencies, but you can create a fake gstreamer0.10-plugins-good package which will satisfy the missing dependency. The simplest way to do this is using equivs:

1. install equivs

    sudo apt install equivs
   

2. generate a template control file

    equivs-control gstreamer0.10-plugins-good.control
   

3. fix the package name

    sed -i 's/<package name; defaults to equivs-dummy>/gstreamer0.10-plugins-good/g' gstreamer0.10-plugins-good.control
   

4. build the package

    equivs-build gstreamer0.10-plugins-good.control
   

5. install it

    sudo dpkg -i gstreamer0.10-plugins-good_1.0_all.deb
   

That should satisfy the opera package’s dependency.