Vintage map style (GL) for Mapbox Studio
From your Mapbox Studio Styles page, click New Style button then select Upload a style tab. Select this .json file and click Create. Next, upload each .svg patterns from the _assets folder. Select texture layers in backgrounds and vintage folders and click Pattern to upload .svg files to your project.
Use the newly created map style's style URL to add to your projects. Read more on how to Create and manage map styles in Mapbox /help page.