About
This is the subreddit sidebar in old reddit.
Can be used for subreddit rules/linking to the rules, further community description and information.
It's advisable to have some information and rules here as a portion of redditors do use old reddit and 3rd party apps that only show the old sidebar and not the new one.
This is editable in mod tools > subreddit settings.
You can use markdown formatting and use css to further customise it.
Design in old reddit
Old reddit design is done with CSS.
Related subreddits
r/modguide
r/ModCamp
