Adding an extra boolean column to "information_schema.columns" or "pg_attribute"

[GPT <gptmailinglists@xxxxxxxxx>]

I would like to add an extra boolean attribute to table columns,
something like NULL. Unfortunately Pg does not support such a feature:

ADD ATTRIBUTE <attribute_name> TYPE <type_of_attribute> TO COLUMN
<schema.table.column_name>;

For example:

ADD ATTRIBUTE is_displayed TYPE boolean TO COLUMN world.human.feature;

so that I can write:

SELECT column_name FROM information_schema.columns
WHERE table_schema = world AND table_name = 'human' AND is_displayed = 'Yes';

Please let me know if there would be any failure of an internal part
or other real technical problem in case I add this extra column by
hand and all relevant stuffs (index, maybe constraint) to either
"information_schema.columns" or "pg_attribute".

I have already been suggested to use VIEW or dynamic SQL but I am
looking something different.

Tia