^^

I do know that the font used for the Scratch logo and the Glow A-Z letters is the Black boys on Mopeds font

The website uses arial.
I believe in 2.0, it also used lucida sans serif (whatever that font was called) when you had that font installed for some reason

I do know that the “Handwriting” font is titled “Handlee”

A-MARIO-PLAYER wrote:

The website uses arial.
I believe in 2.0, it also used lucida sans serif (whatever that font was called) when you had that font installed for some reason

The website uses Arial when it has to fall back from Helvetica because your device doesn't have it downloaded. If you don't have Arial (why) it falls back to your browser's default sans-serif font.

From there it's up to your browser/OS.

For the website and editor, Scratch uses Helvetica Neue, Helvetica, and Arial in that order.
Explanation at the bottom.

In the paint editor, the font names used are different from the actual names of those fonts. These are:

• Sans Serif: Noto Sans
  
• Serif: uses browser default**
  
• Marker: Knewave
  
• Handwriting: Handlee
  
• Curly: Griffy
  
• Pixel: Grand9K Pixel
  
• 中文 (Chinese): Microsoft YaHei, 微软雅黑, STXihei, 华文细黑
  
• 日本語 (Japanese): ヒラギノ角ゴ Pro W3, Hiragino Kaku Gothic Pro, Osaka, メイリオ, Meiryo, ＭＳ Ｐゴシック, MS PGothic
  
• 한국어 (Korean): Malgun Gothic
  

The Serif font uses your browser's default serif font; that's a font with decorations at the ends of strokes.
The default depends on the browser you're using, as well as your operating system. On Windows, this is usually Times New Roman; most browsers allow you to customize this in their settings.

For some fonts, you may have noticed that multiple names are listed. In these cases, Scratch will attempt to load the first font from the list; if this fails, it will then try the next font, then the next, and so on. This helps to ensure that the site will look right for everyone, even if they don't have certain fonts installed.