Salt is a non-essential yet necessary ingredient in bread.
Most kinds of bread in the world contain salt.
Besides giving a good flavour to the bread, salt serves to make gluten stronger.
A dough with no salt is extremely sticky and adheres to the vessel walls where it is kneaded.
The proportion of salt in the regular bread dough is usually 2% by weight of the total flour used.
In this site, all wheat and rye bread formulas have 6 cups of flour and a tablespoon of salt. This is:
6 cups flour (tight and levelled) equals approximately 1 kg flour.
1 tablespoon salt is 15 cubic centimetres of fine salt, equivalent to approx. 20 g of salt; this is: 2% of total flour.
Sweet doughs must take a little salt, otherwise, they are tasteless. I usually use the half the salt used in the common bread. This is 1½ teaspoons per 6 cups or 1 kg flour. That is 1% salt. In some cases, I use only ⅓ teaspoon salt or 1 teaspoon. Salt must be present in all sweetbreads.