under a mat
Unfinished business
An inside job
more to you than me
More to it than meets the eye.
L for large
When proofreading, those three dashes mean capitalize the letter.
under flying seal
1st Class Large Letter
The large letter in the center of the deal indicates the Federal Reserve District.
If you mean, why when I go to a site, the text is in small letters? You can go to your toolbar at the top and under the option VIEW, you should be able to find text or font size, you can change it to large or very large for easier viewing.
Two lines put under a letter typically indicates that the letter is meant to be italicized or underlined. It serves as a formatting instruction for the typesetter or printer, highlighting how the letter should be styled in the final published document.
Cents struck at the Philadelphia mint don't have a mint mark.