If you see something like A1, B2 or C1, these represent the proficiency of a speaker in a language they're not native in, and are called CEFR levels. They are valid for any language, not only German!
Roughly speaking, A levels are beginners and C levels are experts. Remember that CEFR level are self-assessed and indicative!
You can see more specific names and descriptions on the Wikipedia page:
https://en.wikipedia.org/wiki/Common_European_Framework_of_Reference_for_Languages
🗨 How do I know what level I am?
If the table on Wikipedia is too generic for you, you can try using this one here:
https://rm.coe.int/168045bb52
Just check each column one at a time: if you can do all it describes, move to the next column. Your level is the highest where you can do the most things.
Alternatively, you can use this questionnaire to estimate your level more accurately:
https://www.laits.utexas.edu/fi/sites/laits.utexas.edu.fi/files/Self Assessment Checklist European.pdf

(95 uses, 7%, 0.18 uses/day)
(91 uses, 7%, 0.17 uses/day)
(83 uses, 6%, 0.15 uses/day)
(64 uses, 5%, 0.12 uses/day)
(53 uses, 4%, 0.1 uses/day)
(48 uses, 4%, 0.09 uses/day)
(48 uses, 4%, 0.09 uses/day)
(47 uses, 4%, 0.1 uses/day)
(46 uses, 4%, 0.08 uses/day)
(46 uses, 4%, 0.16 uses/day)
(5 uses, 4% 0.01 uses/day)
(4 uses, 3% 0.01 uses/day)
(27228 uses, 7%, 84.19 uses/day)
(23151 uses, 6%, 42.76 uses/day)
(18088 uses, 5%, 33.41 uses/day)
(14628 uses, 4%, 27.02 uses/day)
(13233 uses, 3%, 49.48 uses/day)
(10325 uses, 3%, 40.74 uses/day)
(6307 uses, 5% 11.65 uses/day)
(4320 uses, 4% 7.98 uses/day)
(369 uses, 2%, 0.68 uses/day)
(61 uses, 4% 0.14 uses/day)
(39 uses, 3% 0.1 uses/day)


Text: 69 (30 locked)
Voice: 16 (4 locked)
98290
Level 3 (25 boosts)
