Sandmann's Amazon addons should have the inputstream/widevine installation/update automated.
And just FYI,
there's nothing wrong in 5.90.6 in relation to inputstream/widevine demanding addons (Amazon/Netflix).
for me in a fresh 8.90.4 installation with update to *1001-devel and installing
Netflix with repository.netflix-1.0.1.zip
and libwidevine with getwidevine.sh
Netflix works without problems.
The version of widevine in that script is old and will not work. This version however does MEGA
But I will try the new version to see any differences...
I believe you can also install inputstreamhelper addon and will check your widewine version and ask to update. I'm about 83% sure it does that. Though clicking a Netflix stream won't trigger a widevine update unless your're using a beta fork from the github. The Amazon addon does take full advantage of inputstream helper and widevine updates. Again only 83% sure. Sorry I know this has nothing to do with LE alpha.
and I will also test the inputstreamhelper-addon, thanks for the info...