读书百遍，其义自见。

很欢迎各位同学来推荐、分享好的技术类书籍，大家一起阅读。可以在 issues 区推荐，也可以直接提交 PR。

Barcode image should be displayed on the product page, not only barcode numbers.

Rationale:

• it becomes easier to test our mobile apps with products we don't have physically
• it becomes easier to compare Open Food Facts data with other mobile apps
• it makes data more trustable: I can verify the barcode of my product is the same as displayed on the web page
• some people, for whatever

In the 'Questions' section the text states:

First, let’s download and look at some of the cleaned spreadsheets from the Portal Project dataset.
We’ll need the following three files:

The data was already downloaded in the setup section, and the learners are again reminded to do that at the beginning on of the lesson. I would expect this text to reference the already downloaded files like