With preformatted text, why are some letters red and numbers blue?

When I select text and then hit the preformatted text button in my company’s demo Discourse forum (hosted by Discourse), the default formatting is three apostrophes before and three after the text. However, when I hit the preformatted text button in meta.discourse.org, there is only one apostrophe before and after the text and all text is black.

In my company’s trial Discourse, three apostrophes make certain letters red and all numbers blue. There is also a scroll bar below the text.
However, in meta.discourse.org, the same three apostrophes don’t affect the colour of the text.

Here’s how it looks in my company’s trial Discourse forum:

Here’s how it looks here on meta.discourse.org:

abcdefghijklmnopqrstuvwxyz 0123456789
abcdefghijklmnopqrstuvwxyz 0123456789

The code block is formatted using the default code lang Site Setting. On meta, we have that set to text.

You can override that per block by specifying the language after the initial fence.


Thank you again, @supermathie ! Now that I know this, I will explore more options in Select the programming language used in code blocks.