Robots
The robots module isn't enabled by default. You enable it by adding the following line to your Program.cs file:
app.UseMiddleware<RobotsMiddleware>();
The RobotsMiddleware class can be found in the Limbo.Umbraco.Seo.Robots namespace. When enabled, the robots file can be found at /robots.txt.
Properties
By default the sitemap module is backed by the SitemapService class, which looks for a number of properties that you can then use to control the sitemap:
robotsTxt
Add a textarea property with this alias to the site node to allow users to add custom rules to therobots.txtfile.