The latest update of Visual Studio 17 (15.5.5) introduces a new backup folder called "ServiceFabricBackup" before upgrading service fabric applications.

* Add *.snk strong name key files

Strong name key files shouldn't be included in a repository AFAIK. they are intended to sign build output to verify that it comes from the correct publisher. having an *.snk in a repository would allow anyone to produce build as if they were the original publisher.

I guess some OSS projects might like to have *.snk files in their repos but that would be an exception to the rule.

* Make use of *.snk optional

Add note explaining use.

* Reduce explanation

Just use a link instead

ref http://msbuildlog.com/

* Update VisualStudio.gitignore

It looks like VS2017 changed it's nuget package directory name to be capitalized.
When using Ubuntu for Windows, directory name casing of NuGet package folder becomes important and detected as a change by git,. This change is to ignore regardless of casing.

AxoCover is a Code Coverage Tool. It creates a **.axoCover** folder where are created:
- settings in settings.json
- sub-folders into **run** folder which contain code coverage results.

All content into **.axoCover** folder must be ignored except the **settings.json** file.

for .appx files created in the project root directory.

Secondary data files .ndf (https://msdn.microsoft.com/en-us/library/ms189563.aspx)

- It is recommended to include the packages.config file when using Cake
- This ensures that the Cake version that is being used is *pinned* and updated only when the user decides

If the .gitignore file is inlcuded in another project, it may be feasible to have a reference to origin.

Reference: http://stackoverflow.com/questions/1826901/should-i-add-vcxproj-filter-files-to-source-control

see e.g.
http://stackoverflow.com/a/1530193
https://msdn.microsoft.com/en-us/library/aa241721(v=vs.60).aspx

Cake.Net creates a tools folder at the root which contains downloaded packages and should not be checked in.

.jfm files have started blocking checking for .sqlproj projects in Visual Studio. .jfm files are a new file-type created by the Microsoft ESENT database engine - this is a recent improvement only in Windows 10 Anniversary update. As the SSDT .sqlproj type in Visual Studio uses this engine for .dbmdl metadata files, and this file is locked by the user, this currently blocks users from checking into Git repositories.

This fix helps mitigate this by avoiding checkin of this file type.

__pycache__/
*.pyc

I've just upgraded to ASP.NET Core RC2, and I've found that Visual
Studio is producing a file called project.fragment.lock.json. When I
delete the file it is recreated during build. Given project.lock.json is
already ignored this looks like another file to ignore.