wrap-prefix

wrap-prefix is a variable defined in `C source code'.
Its value is

nil

• Automatically becomes buffer-local when set.

Documentation:
Prefix prepended to all continuation lines at display time.
The value may be a string, an image, or a stretch-glyph; it is
interpreted in the same way as the value of a `display' text property.

This variable is overridden by any `wrap-prefix' text or overlay
property.

To add a prefix to non-continuation lines, use `line-prefix'.