Without more context, it's hard to decode exactly. However, the format "Download- [ciphertext]" suggests this might be a puzzle where you need to decode the filename or link.

It looks like you've shared a snippet that appears to be encoded or encrypted — possibly a simple cipher like a Caesar cipher, Atbash, or substitution cipher.

Given the end "mgh..." might be "the" or similar.

The text: Download- tjmyt nwdz w ms w nyk lfrst swryt mgh...

Could it be a keyboard shift? Sometimes people type with hands shifted one key on QWERTY. "tjmyt" with each key shifted left on QWERTY: t→r, j→h, m→n, y→t, t→r → "rhntr"? No.