The "Repository Browser" URL is not saved anymore. The value of the popup itself (githubweb, gitoriousweb, etc) is saved, though.
We just upgraded Jenkins from 1.501 and git-plugin 1.1.26.
Furthermore, with existing jobs that still have the URL, when you configure and save them without any change, the URL gets removed.
Looking at the Job Config History, it shows that the <refspec> was removed (but that was empty), and also the <url> inside of the <browser class="hudson.plugins.git.browser.GitoriousWeb"> tag
|Field||Original Value||New Value|
|Priority||Minor [ 4 ]||Major [ 3 ]|
|Status||Open [ 1 ]||Resolved [ 5 ]|
|Resolution||Fixed [ 1 ]|
|Status||Resolved [ 5 ]||Closed [ 6 ]|
|Workflow||JNJira [ 154143 ]||JNJira + In-Review [ 207479 ]|