CHAPTER 50: Inspect actual before-and-after website files

Boards: 50a and 50b.
Read the surrounding chapter before this lab. All examples are original and synthetic.

PREDICT
Predict which local targets are missing in each version. The lab reads the original HTML and robots files through the supplied HTML parser and checker. It does not alter the website.

RUN
From the companion root, run:
python visual_labs/ch50/walkthrough.py
Use python3 if that is your configured command.

COMPARE
Compare the printed values and explanations with both boards. Read expected_output.txt after making your prediction. An assert checks a known expected result and stops if it differs. Temporary output folders are removed after the demonstrations; original course files are not edited.

CHANGE ONE THING
In your own working copy, change only the visible quote link wording while retaining the missing href. The missing-target issue remains. Then repair href and follow the route in a browser. A local parser check cannot demonstrate live indexing, commercial improvement or complete keyboard usability.

EXPLAIN
State which input changed, which instruction handled that change, and why the resulting output is appropriate. If your prediction differs, identify the first step at which it diverges. Return to the surrounding lesson before adding more complexity.
