2-indent is a literal block. 4-indent also is, but only because it's a 2-indent.
HN markup also supports \-escapes (so you can write \*hello\* to get *hello*), but they grow linearly, not exponentially, with repeated escapes (\\\* becomes \\*). It also truncates long URLs in display, and it handles a single pair of parentheses in them (so you can write https://example.com/print(%22Hello,%20world%21%22)). But I think that's all.
HN markup also supports \-escapes (so you can write \*hello\* to get *hello*), but they grow linearly, not exponentially, with repeated escapes (\\\* becomes \\*). It also truncates long URLs in display, and it handles a single pair of parentheses in them (so you can write https://example.com/print(%22Hello,%20world%21%22)). But I think that's all.