Git is a term used for version control system to easily track changes in one or more of files. Git is a source code repository where developers keep track of their source code using Git.
Branch is a temporary copy of source code for a single purpose like adding a particular feature or fixing a bug.
Merge is safely moving the changes from one branch back to another – usually, merge to master.
Jira Server is a self-hosted Jira Software which runs centrally on your own server; be it hosted by AWS or other hosting services.
Jira Cloud is a part of the Cloud service hosted by Atlassian and sells them as a subscription service.
The issue key is a combination of project key and issue number. For example, the project key is called TEST and there's an issue #123 in the TEST project. The resulting issue key would be TEST-123. Include the issue key in the commit message so that the pushed commits will be associated to that issue and can be viewed inside Jira.
Remote repository is the central hosting used by your team for pushing commits and pulling updates.
Local repository clone
Clone of remote repository is located on the same server as your Jira service. It is cached locally for performance reasons and queried every time the list of git commits is displayed.
Lucene is an index service within your Jira instance. It ships with Jira and Git Integration for Jira app also makes use of it.
This database stores information about all commits (comment, author, etc) as well as the branch name which the commit belongs to.