Browser caching stores webpage resource files on a local computer when a user visits a webpage. “Leveraging” browser caching is when a webmaster has instructed browsers how their resources should be dealt with.
How to Fix Leverage Browser Caching With .htaccess File ?
Create a .htaccess file with following code or insert this code in your .htaccess file. I will fix your leverage browser caching issue except 3rd part website.