Transformation of an object into parameter value on submission of request


Today I saw rather a weird phenomeon, when submitting a request spontaneoulsy.

The URL I typed looked something like below:

https://example.com/en/trade/pro?layout= and when submitted it transformed into https://example.com/en/trade?layout=pro

If I correctly perceived that the pro object moved to a value of layout (if not just visually).

It didn’t work for https://example.com/en/trade/test?layout= and when submitted should transform into https://example.com/en/trade?layout=test, that didn’t work.

It did only work for the pro object.

Is this a behavior made by developers of the site or could this eventually lead to something interesting?