Snippets are small fragments of reusable code which, in all the major text editors, can be defined, organized and associated to key shortcuts. Although in Vim it is possible to create snippets without using any plugin, Ultisnips provide us extra features and write snippets using a clean and well documented syntax.
Vim is definitely one of the most venerated text editors in the Unix world. Although its learning curve can be pretty steep when accustomed to more traditional text editors, its usage can dramatically improve productivity. A lot of plugins are available for the editor; almost always their source code is hosted on Github or similar platforms based on Git. To manage such plugins, several third-party plugin managers were developed in time, such as Pathogen or Vim-Plug, but since version 8 of the editor, a native way to manage plugins was introduced.