Hello GitHub experts!

Recently I found that the https://github.com/robots.txt has prevented all repo contents from being crawled by search engines. Here is the current content of the robots.txt.

# If you would like to crawl GitHub contact us at support@github.com.
# We also provide an extensive API: https://developer.github.com/
User-agent: baidu

crawl-delay: 1
User-agent: *
Disallow: */pulse

Disallow: */tree/

Disallow: */blob/

Disallow: */wiki/

Disallow: /gist/

Disallow: */forks

Disallow: */stars

Disallow: */download

Disallow: */revisions

Disallow: */issues/new

Disallow: */issues/search

Disallow: */commits/

Disallow: /commits/?author

Disallow: /commits/?path

Disallow: */branches

Disallow: */tags

Disallow: */contributors

Disallow: */comments

Disallow: */stargazers

Disallow: */archive/

Disallow: */blame/

Disallow: */watchers

Disallow: */network

Disallow: */graphs

Disallow: */raw/

Disallow: */compare/

Disallow: */cache/

Disallow: /.git/

Disallow: /.git/

Disallow: /.git$

Disallow: /search/advanced

Disallow: /search

Disallow: */search

Disallow: /q=

Disallow: /.atom
Disallow: /ekansa/Open-Context-Data

Disallow: /ekansa/opencontext-*

Disallow: */tarball/

Disallow: */zipball/
Disallow: /account-login

Disallow: /Explodingstuff/

I believe that by Disallow: */blob/, none of repo contents can be crawled.
I remember that previously GitHub allows master branch to be crawled. Could you share what’s the intention of this change? What should I do if I want my repo contents to be indexed by Google?