With this product-specific custom field you enter the desired title for the corresponding download. It is displayed as the label of the download link on the product page.
Each of the three downloads (Download 1–3) has its own title field.
You can find the "Download 1 – Title" custom field in the respective product:
Tab "Specifications" ⇒ Block "Custom fields" ⇒ Tab (Set) "Downloads (... Pro)"
Type: Text
Technical name: twt_{theme}_{edition}_custom_field__product__download_1_title