I knew that that the <html> tag can be fully omitted (and some others, like <body> and <title> IIRC), but if I read that it can also be partially omitted. So yo

I knew that that the <html> tag can be fully omitted (and some others, like <body> and <title> IIRC), but if I read that it can also be partially omitted. So you're allowed to open it but not close it, or close it but don't open it. That's new to me. I've tried omitting those tags, but I decided that in the end things are easier to read when you do include them, so nowadays I always include them when I write HTML.