Rust: What is the difference between Box<dyn Error> and anyhow::Error?

1// Box<dyn Error>
2fn read() -> Result<String, Box<dyn std::error::Error>> {
3    let s = std::fs::read_to_string("file.txt")?;
4    Ok(s)
5}
6
7// anyhow
8fn read() -> anyhow::Result<String> {
9    let s = std::fs::read_to_string("file.txt")
10        .context("Failed to read config")?;
11    Ok(s)
12}