Azure pipeline yml: how to print out value of a variable

It seems that name is a special magic variable that somehow gets used for my output directory. (Is this behavior documented anywhere?)

I'm trying to set it.

Given the extraordinary difficulty of writing Azure pipeline yml, it's highly unlikely that I'll get it right. In the absence of any form of debugging I want to add a print statement so that I can see the value.

How?

  ${{ if eq(variables['Build.SourceBranchName'], 'master') }}:
    buildConfiguration: 'Release'
    tag: ''
    
  ${{ if ne(variables['Build.SourceBranchName'], 'master') }}:
    buildConfiguration: 'Debug'
    tag: ${{ format('-{0}', variables['Build.SourceBranchName']) }}

# How do you do string concatenation in yml? Do I need to do `format` like above?
name: $(Build.BuildId)$(tag)

steps:

- script: echo "name is $(name)"

But the output is

Generating script.
Script contents:
echo "name is $(name)"
...
name is $(name)"

Is it possible to make this work? How?