We have options for controlling the maximum diff upload size, and for

setting the threshold of number of lines before syntax highlighting is

disabled. However, these were never given reasonable defaults.
Now, the diff upload size is set to 2MB as a default, and the syntax

highlighting is set to 20,000 lines.
These will only be set for brand-new installations. Existing installs

will retain any stored settings.

Created a new database, viewed the settings page, and saw the values.
Verified these through siteconfig debug output.