Why do German umlauts and sharp s (ß) work without a package in LaTeX?

Question

I am used to the fact that LaTeX will only know letters like ä, ö, ü, or ß if I use packages like

\usepackage{ucs}
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}

Today, I tried LaTeX on a Mac for the first time, using the MacTeX distribution and texmaker. Without writing down any packages, all umlauts and ß were accepted correctly from scratch. Why is that and will the usage of special letters without using the packages cause any problems?

Answer 1

Since the April 2018 release, LaTeX considers UTF-8 as default input encoding

Thus calling \usepackage[utf8]{inputenc} at the start is no longer required. If a file has a different encoding than UTF-8, the proper encoding should, of course, be declared.

The utf8x add-on, together with the ucs package, used to be needed for some special application or, mostly, for typesetting Greek. The situation has very much changed and utf8x should be avoided (also ucs) as it has been unmaintained for several years and utf8 (the default) behaves much better.

On the other hand, loading fontenc is still required in order to use the T1 encoding and get better results with hyphenation of words containing accented letters or special glyphs used in European languages.

Why don't manuals and guides mention this? Because inertia prevails. :-(

Answer 2

I don't have enough reputation to comment, but I'd like to add that in 2022 (after April 2018?) \usepackage[T1]{fontenc} is not just unnecessary but can be harmful for certain engines.

I used to include these packages in BibTex, together with \usepackage[ngerman]{babel} , following some old tutorials. ä ö ü worked fine but every ß was complied to SS.

This problem is solved by this question and an another explanition here( see https://tex.stackexchange.com/a/641959/278331)

In 2022 for unicode-aware engines as XeTex and LuaTex, just delete all of these package declarations

\usepackage{ucs}
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}

then you would be able use all letters from ä to ß in source code directly

Edit: \usepackage[ngerman] is still required for a correct hyphenation