Describe what is wrong or what you would like, then file it as a GitHub issue or send it by e-mail. Either one opens a draft for you to read and edit first; nothing is sent until you send it. Every report gets a reply.
Reporting something on a map? Use the form inside the app instead (“Report a bug or leave a comment” at the foot of its panel): it attaches the point and layers you were looking at. The apps: Illinois, New York, San Francisco, Wisconsin, Iowa, Michigan, Minnesota, Kentucky, Indiana, North Carolina, Oklahoma, South Carolina, Tennessee, Arkansas, Mississippi.