Viewing history of changes in a repository
Upsource entry page displays configured projects, where each project corresponds to a specific VCS repository.
To open a particular project, just click its name. The project home view will be displayed:

In the main pane you see a list of recent revisions of that project displayed in chronological order.
Each entry shows:
a committer userpic (if any)
a committer username
a branch name
a commit message
a revision ID
a commit timestamp (when the commit took place)
a review icon (
open and
closed) and ID linking to the review (if this revision is included in a review)
a discussion counter
(shows the number of discussion threads if this revision contains any)
View options allow you to customise the way the revision list is displayed:

The list is displayed in a Full view by default. Switching to a Compact view hides userpics and lets the list take less space in your browser window:

You can also expand all revision entries to show affected files contained in each revision.
Clicking
The list of revisions is accompanied by a commit graph that helps visualize the history of commits, branches, and merges in your repository:

You can hide it using View options.