_v field in documents created in MongoDB

System Information
  • Strapi Version: 3.6.5
  • Operating System: Linux
  • Database: MongoDB 4.0.10
  • Node Version: 12.22.12
  • NPM Version: 6.14.16
  • Yarn Version:

Hello,

Every collection’s document that is created contains a _v field, which is defaulted to 0.
What is the use of that field?