naga0ka Earlier you ran into issues because your repo was named naga0ka/flarum-ext-japanese-locale but your Packagist record was named naga0ka/flarum-tra-ja (as it is now). So when you tried to use
composer require naga0ka/flarum-ext-japanese-beta6
Composer couldn't do anything because it couldn't find a matching record on Packagist. The composer command has to match the name of your Packgist record exactly, or it won't be able to do anything.
Now it seems you've changed your repo name to match your Packagist record ... so I'm not sure what difficulty you are having. Still, let's go back to the start and check everything.
First, regarding your repo: I'd strongly recommend that you stick with the standard format for the repo name. This is especially important if you want to make your language pack available via the planned Flarum Marketplace one day.
In your case, it should be naga0ka/flarum-ext-japanese. The "flarum-ext-" indicates it is a Flarum extension. Spelling out the name of the language is also a good idea, as that way it is more readable to folks who aren't familiar with locale codes.
So ... you should change the name of your repo as shown above, then edit the second line of your composer.json to match it exactly. Then you should change the name of your Packagist record and the canonical repository URL to match it. Keeping everything the same will make mistakes more difficult.
Make those changes, then try running the command
composer require naga0ka/flarum-ext-japanese
That command should be all it takes to install your language pack. Give it a shot and let us know if it works!
Note: You don't have to create a new repo to change the name ... you can change the name by clicking "Settings" on the repo page in GitHub.
