For a given project, I have four build pipelines, each pipeline Trigger has CI enabled, each has a branch filter for a single branch - master, Staging, QA, development. These work successfully, any completed pull request to one of those four branches are successfully kicking off a build process.

This morning, I created a new branch based off "development" branch. IT was a one-liner change, so I decided to make the change online in the browser using DevOps editor. I saved the change. 

Immediately after saving the change online, I saw a new build pipeline was created (I had received an email saying my build failed). What caused the new Build pipeline to be created?

The new build pipeline looks to be auto-created, it is pure YAML:

```
pool:
  vmImage: 'Ubuntu 16.04'

variables:
  buildConfiguration: 'Release'
  BuildPlatform: 'Any CPU'
  Parameters.solution: = '*.sln'
  Parameters.ArtifactName: = 'xxxxxx'

steps:
- task: NuGetToolInstaller@0
  displayName: 'Use NuGet 4.4.1'
  inputs:
    versionSpec: 4.4.1

- task: NuGetCommand@2
  displayName: 'NuGet restore'
  inputs:
    restoreSolution: '$(Parameters.solution)'

- task: VSBuild@1
  displayName: 'Build solution'
  inputs:
    solution: '$(Parameters.solution)'
    platform: '$(BuildPlatform)'
    configuration: '$(BuildConfiguration)'

- task: PublishSymbols@2
  displayName: 'Publish symbols path'
  inputs:
    SearchPattern: '**\bin\**\*.pdb'
    PublishSymbols: false
  continueOnError: true

- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)'
    ArtifactName: '$(Parameters.ArtifactName)'

```

In the project, there were no pull requests created, and my private branch, I can see my change. 

The email I received had this in the title (actual names removed):

> 
> [Build failed] MyProjectName CI - MyProjectName:MyBranchName - MyProejctName - bf9524f9
> 
> 
> 

========

EDIT
====

I just found there is an azure-pipelines.yml file in the root folder of the branch. the contents match the above. Is this competing with the designer pipelines?