Modify the label that appears above a Relate field's search box

This is rendered using label - LBL_SEARCH_SELECT_MODULE, and is formatted as "Select {{module}}" by default. You can update this label just for your module in custom folder for your requirement :) 

Would you mind telling me the full deployment path for the label file? It's tricky finding it since I'm cloud only

Would you mind telling me the full deployment path for the label file? It's tricky finding it since I'm cloud only

LBL_SEARCH_SELECT_MODULE is defined in the app_strings (include/language/en_us.lang.php) but you can define in the mod_strings so the changes will affect a specific module instead of whole relate fields.