I'm replying directly on the thread because one of the comments didn't arrive in Friendica, yet (I'm seeing only 3 of 4 comments here on Friendica, I only could see the fourth comment through Lemmy).
The suggested Forgejo (with public "instances" such as Codeberg) and Vervis seem good and promising. While they're not exactly what I'm looking for (as Github Gists and Opengists are less than a software forge and more like a "Pastebin/Ghostbin", they're meant to allow sharing "repoless" code (they also have some Git integration, but there are no such things as branches, CI/CD, issue tracking, etc)), they're useful to me, too, thanks everyone for suggesting them.
@scott I'm looking for something alternative to Github Gists, so I could quit it and go to a decentralized platform. Not the GitHub itself, but Github Gists, which is more like a multi-file "pastebin".
Something decentralized, federated, something akin to Writefreely where posts outside Writefreely (e.g., when seen from Mastodon) shows up as a shortened/summarized version, but tailored for code sharing, allowing for syntax highlighting, proper Markdown rendering and allowing for multiple text files within the same publication ("parts" within the "whole", each one having their own filename; by "files", I mean text files and source code such as .mjs, .js, .rb, .md, .txt, .csv, etc... not binary files such as images or movie-clips or audio or executables or zip/tarball/rar archives). Something that I could choose between hosting it myself (i.e., having my own instance) or using an existent instance, with the possibility of migration between instances (similar to Mastodon's Export feature, but also allowing for importing exported publications).
The closest thing would be @Daeraxa suggestion, Distbin (sorry Daeraxa for not getting to reply your comment yet, Friendica didn't deliver it to me yet, but I saw your comment through Lemmy and I tested Distbin here). Sadly, as Daeraxa mentioned, that project is abandoned, with the last commit dating back from 6 years ago. Also, there are several issues (publications are anonymous because there's no account system, publications can't deal with multiple "files", no deletion mechanism, etc). It's the closest thing, but not the thing.
Software forges (such as Vervis, Gitea and Forgejo) are really good for full projects. However, while I sometimes create full projects (where software forges, branches and forks, pull requests, CI/CD pipelines and source versioning would apply), the majority of my dev portfolio is composed of small-to-medium-sized code snippets experimenting with Node.js/Javascript, Python, Ruby and Shellscript, sometimes one-liner code snippets, and wrapping them up within full repos is overkill.
Maybe I'm going to do a solution myself in the future, I'm not sure, it's not exactly a plan or a promise. The core functionality seems simple to develop (looking at the Distbin's source, it seems really simple) but integrating with ActivityPub and relaying info about multiple files within a publication in a format that's compatible with other fediverse platforms (Mastodon, Friendica, etc) is a whole other story, in parts because I'm yet to learn about the technicalities of ActivityPub (i.e. how it really works behind the scenes beyond the
/api/v1
calls).