Given a section of CICD pipeline in Gitlab, what is the difference between `${vProj2}` and `$vProj2`?

Sample.yml

# In a GitLab CI/CD pipeline (and in shell scripting), both `$vProj2` and `${vProj2}` are used for variable expansion, 
# but there is a subtle difference:

# - **`$vProj2`**: Expands the variable `vProj2`. This is the simplest form and works when the variable name is immediately 
# followed by a character that cannot be part of a variable name (like a space or punctuation).

# - **`${vProj2}`**: Also expands the variable `vProj2`, but the braces are used to clearly delimit the variable name. 
# This is especially useful when you want to append characters directly after the variable name, e.g., `${vProj2}_suffix`, 
# or when the variable name is followed by a character that could be interpreted as part of the name.

# **Summary:**
# - Use `$vProj2` for simple cases.
# - Use `${vProj2}` when the variable name needs to be clearly separated from surrounding text or when appending characters 
# immediately after the variable.

# Both forms are valid and expand to the value of `vProj2`, but braces provide clarity and prevent ambiguity 
# in more complex expressions.

variables:
  vProj2: myvproject2

before_script:
  - export PROJECT2=${vProj2}
  - echo $PROJECT2              # return myvproject2
  - echo ${PROJECT2}            # return myvproject2
  
  - export PROJECT3=$vProj2
  - echo $PROJECT3              # return myvproject2
  - echo ${PROJECT3}            # return myvproject2