• Kotlin: “are you talking to me?”

This could be useful. I will add it in the to-do list.

“Tags” are similar to twitter hashtags, you can use them to categorize a post. For example, if you create a post about Android you can add the tag “android” (without “#”). When you manage a magazine you can add one or more tags (always without “#”) to see posts of the fediverse with that tag.
I have no idea about “badges” :)

I added it in the latest version.

I would prefer not to spam kbin about this application, but if you think it might be useful to others you are free to post a link in other magazines/fediverse. Thanks for the tip about Obtainium.