The git version is 2.7.4.
I am using the stand alone server (tracd), and nothing stands out to me in the log file.
Here is the full log output (with some IPs and paths retracted) associated with just the request to display the file contents.
2018-06-15 13:01:20,075 Trac[env] WARNING: base_url option not set in configuration, generated links may be incorrect
2018-06-15 13:01:20,075 Trac[main] DEBUG: Dispatching <RequestWithSession "GET '/browser/escdtn/cfs/apps/bm/src/bm_app.c'">
2018-06-15 13:01:20,078 Trac[main] DEBUG: Chosen handler is <Component trac.versioncontrol.web_ui.browser.BrowserModule>
2018-06-15 13:01:20,087 Trac[git_fs] INFO: detected GIT version 2.7.4
2018-06-15 13:01:20,088 Trac[PyGIT] DEBUG: PyGIT.Storage instance for '/..../escdtn.git' is constructed
2018-06-15 13:01:20,088 Trac[PyGIT] DEBUG: requested weak PyGIT.Storage instance for '/..../escdtn.git'
2018-06-15 13:01:20,088 Trac[git_fs] DEBUG: enabled CachedRepository for '/..../escdtn.git'
2018-06-15 13:01:20,089 Trac[session] DEBUG: Retrieving session for ID u'admin'
2018-06-15 13:01:20,105 Trac[PyGIT] DEBUG: Detected changes in git repository '/..../escdtn.git'
2018-06-15 13:01:20,105 Trac[PyGIT] DEBUG: triggered rebuild of commit tree db for '/..../escdtn.git'
2018-06-15 13:01:20,114 Trac[PyGIT] DEBUG: rebuilt commit tree db for '/..../escdtn.git' with 94 entries (took 8.6 ms)
2018-06-15 13:01:20,128 Trac[api] DEBUG: action controllers for ticket workflow: ['ConfigurableTicketWorkflow']
2018-06-15 13:01:20,136 Trac[chrome] DEBUG: Prepare chrome data for request
2018-06-15 13:01:20,142 Trac[browser] DEBUG: Rendering preview of node bm_app.c@None with mime-type text/x-csrc; charset=utf-8
2018-06-15 13:01:20,143 Trac[api] DEBUG: Trying to render HTML preview using PygmentsRenderer [lineno]
2018-06-15 13:01:20,284 Trac[main] DEBUG: Rendering response from handler
2018-06-15 13:01:20,734 Trac[main] DEBUG: Dispatching <RequestWithSession "GET '/chrome/site/your_project_logo.png'">
2018-06-15 13:01:20,735 Trac[main] DEBUG: Chosen handler is <Component
trac.web.chrome.Chrome>
2018-06-15 13:01:20,789 Trac[main] DEBUG: Dispatching <RequestWithSession "GET '/chrome/common/topbar_gradient.png'">
2018-06-15 13:01:20,790 Trac[main] DEBUG: Chosen handler is <Component
trac.web.chrome.Chrome>
2018-06-15 13:01:20,793 Trac[main] DEBUG: Dispatching <RequestWithSession "GET '/chrome/common/topbar_gradient2.png'">
2018-06-15 13:01:20,794 Trac[main] DEBUG: Chosen handler is <Component
trac.web.chrome.Chrome>
2018-06-15 13:01:20,811 Trac[chrome] WARNING: File your_project_logo.png not found in any of ['/..../trac/htdocs']
2018-06-15 13:01:20,811 Trac[main] WARNING: [....] HTTPNotFound: 404 Not Found (File your_project_logo.png not found), <RequestWithSession "GET '/chrome/site/your_project_logo.png'">, referrer 'http://..../browser/escdtn/cfs/apps/bm/src/bm_app.c'
2018-06-15 13:01:20,812 Trac[chrome] DEBUG: Prepare chrome data for request
2018-06-15 13:01:20,815 Trac[session] DEBUG: Retrieving session for ID u'admin'
2018-06-15 13:01:20,822 Trac[PyGIT] DEBUG: requested weak PyGIT.Storage instance for '/..../escdtn.git'
2018-06-15 13:01:20,822 Trac[git_fs] DEBUG: enabled CachedRepository for '/..../escdtn.git'
2018-06-15 13:01:20,988 Trac[session] DEBUG: Retrieving session for ID u'admin'
2018-06-15 13:01:21,015 Trac[session] DEBUG: Retrieving session for ID u'admin'