Use case or problem
Currently Markdown blocks within HTML blocks are not parsed, as an optimization to handle large files. However, this makes it cumbersome to use e.g. <details>/<summary> HTML tags.
Obsidian should use a treshold file size for toggling its large file optimizations: only when a file’s size is above the treshold, would the large file optimizations be enabled. However, Obsidian should still allow the optimizations to be disabled.
Compare this with VS Code, for example: when opening a large file, it notifies that some features are unavailable due to the large file size. But the user is still able to forcefully enable the features:
Current workaround (optional)
Foldable callouts have been proposed as an alternative, but these are neither valid CommonMark nor recognized by VS Code’s parser. (And in a semantic sense “callouts” are kind of the opposite of “details”.)