They really are not very consistent. Markdown/HTML is rendered and displayed differently on all platforms...

• GitHub releases: Looks OK, if not ideal due to a duplicate heading - I doubt anyone cares, though
• Overwolf app: CF doesn't show changelogs
• WowUp: Website - looks good to me - app doesn't show changelogs
• CurseForge: Readable, although a bit awkward
• WowAce: Looks OK

On the topic of Discord changelog, it seems that this could (and should) be automated: Whenever a release is created, a bot (or webhook) could post the changelog from GitHub's release. They at least support proper Markdown formatting in every case.

Discord changelogs have been disabled, until automation is set up for them.

It looks like this problem has solved itself. CF still isn't great about honoring markdown, but it's readable at least...

It appears no matter which format I use, it will be messed up in at least one of the channels... In order to make it manageable, I think some limitations should be put in place:

• The Curse/WowAce project site view is deemed irrelevant, as it breaks most often and isn't something most users would actually visit. Example: https://www.wowace.com/projects/rarity/files/3227299 (That's them choking on basic markdown syntax...)
• Change logs displayed on the main project site should probably be rendered correctly. I think it mostly uses the same logic, but apparently it's not quite identical (sigh). Example: https://www.curseforge.com/wow/addons/rarity/files
• The Twitch app/Overwolf app (or whatever official way there exists now) will be ignored, as wowup.io seems a much better (and open source) alternative. It doesn't currently display change logs, but if it ever does they should also be rendered correctly
• Formatting should ideally be limited to the subset available in Discord channels (no headings/HTML), so that they can be copy/pasted in without having to manually change anything