The phrase "a feather in one's cap" means to have an achievement or accomplishment that can be proudly displayed as a symbol of success. Full definition
It's likely a big feather in the cap for Essential and it could persuade many people to consider this new phone that's now available to pre-order. (androidauthority.com)
It would be one more feather in its cap and appeal to an even wider audience. (shortpause.com)