I decided I might migrate from Chromium browser to Ungoogled Chromium so I went to the chromestore to add UBlock Origin Lite and I discover this ... 
google is totally out of control ... I truly hope the USDOJ completely breaks up this evil monopoly.
It's also defunct on Chromium.
The same creators:
The history of this:
I followed your link on my Floorp browser and it showed available so I copied and paste your link into Ungoogled Chromium and voila I get the same page I post a screenshot above "Item currently unavailable" So it would seem google hates Ungoogled Chromium as much as they hate Ublock origin,
Unless I'm missing something eg. can only be done in developer mode?
I use Ungoogled Chromium... But... I am not at this moment.
Since Zorin OS changed default to Brave Browser, I have been testing Brave Browser in order to enhance my knowledge for forum use.
And the Ublock Origin Lite extension is available on Brave.
Since API changes resulted in the original issue - my first suspicion would be that the Ungoogled Chromium uses an older base than the current chromium release.
Doesn't Brave comes with their super addblocker? Seen some ads about it on Facebook.
I've used Brave for years and years as one of my many browsers I use (I use different browsers for all important sites) and I can confidently say this about Brave, you do not need an additional adblocker Brave is very efficient at blocking ads, it blocks you tube ads as well as Ublock Origin original V2 does.
They have an own one. But of Course You can install more.
Brave at the Moment still supports Manifest V2 as far as I know. So, it should be possible to install the ''normal'' uBlock Origin, too. I have it installed.
I had not thought to look - indeed, that shows as available.
Brave is wonderful for the default browser.
Sometimes the chrome web store can incorrectly detect ungoogled chromium as unsupported; have you installed the chrome web store extension suggested in the initial setup? And if the answer is yes, have you tried refreshing the page up to 4 times? Sometimes that works for me to solve that error.
I tried your suggestion, it didn't work and continues to display "file currently unavailable" on Ungoogled Chromium obtained through Zorin Software store and is up to date ... I did check on Brave and seen UBlock Origin (original) was available and downloaded it to Brave but disabled it as it seems unnecessary for me with Brave at the moment as I only use Brave for a few tasks I do, mostly non-daily tasks.
Just a quick note to share that it's still available for me on Vivaldi. No issues.
