The Y-namespace is meant to be used for centrally developed solutions or also known as head office while the Z-namespace is used for local developed solutions or also known as branch office. But at the end of day, it all depends on the developer how he uses it.

First of all, don’t use WS_DOWNLOAD as this is obsolete.You can use a character type field and set it to cl_abap_char_utilities=>cr_lf. Now use this field at places where you want to insert the new line.