Unexpected `$<2>` added to output when TERM=vt520

info: downloading installer
$<2>
Welcome to Rust!
$<2>
This will download and install the official compiler for the Rust
programming language, and its package manager, Cargo.

Rustup metadata and toolchains will be installed into the Rustup
home directory, located at:

  /home/lex/.rustup

This can be modified with the RUSTUP_HOME environment variable.

The Cargo home directory is located at:

  /home/lex/.cargo

This can be modified with the CARGO_HOME environment variable.

The $<2>cargo$<2>, $<2>rustc$<2>, $<2>rustup$<2> and other commands will be added to
Cargo's bin directory, located at:

  /home/lex/.cargo/bin

This path will then be added to your $<2>PATH$<2> environment variable by
modifying the profile files located at:

  /home/lex/.profile
  /home/lex/.bashrc
  /home/lex/.zshenv

You can uninstall at any time with $<2>rustup self uninstall$<2> and
these changes will be reverted.

Current installation options:


$<2>   $<2>default host triple: $<2>x86_64-unknown-linux-gnu$<2>
$<2>     $<2>default toolchain: $<2>stable (default)$<2>
$<2>               $<2>profile: $<2>default$<2>
  modify PATH variable: $<2>yes$<2>

1) Proceed with installation (default)
2) Customize installation
3) Cancel installation
>

Reproduce the installer output with TERM=vt520 and compare it with another terminal setting. Trace the installer’s prompt rendering and determine why literal <$2> markers appear; done means the displayed output no longer contains them while preserving the intended formatting.