With this product-specific custom field you enter the desired title for the corresponding video. It is displayed as the label of the video on the product page.
Each of the three videos (Video 1–3) has its own title field.
You can find the "Video 1 – Title" custom field in the respective product:
Tab "Specifications" ⇒ Block "Custom fields" ⇒ Tab (Set) "Videos (... Pro)"
Type: Text
Technical name: twt_{theme}_{edition}_custom_field__product__video_1_title