What are some alternatives?
OpenBrand - OpenBrand helps designers, agencies, and brands work together. It is a smart home for all your logos, designs, and other creative stuff.
zeroheight - Organize and share your design libraries
Identihub - Self-hosted Open Source brand & assets management software
pilcro - Get all your brand assets in one place with free brand guideline software. Access your brand assets quickly, save and share with Google
Brandfolder - One link to all your marketing assets. Brandfolder is your convenient source to visually organize, quickly find and easily share all your final brand assets.
Frontify Style Guide - Create beautiful web-based brand manuals in minutes