Translations:(streams)/23/en

• The first one is the title. It is not supported by typical ActivityPub-based projects.
• The second one is the summary. It uses the abstract field, the same that Mastodon and others use for content warnings. A summary makes sense, considering how long posts can be.
• The third one is for categories. It is only used to find posts within the channel; it's the only field that isn't federated except to nomadic clones.
• The fourth one is the text body.