This phrase is the name of the first chapter in Oliver Twist. Let's take a look at a few other chapter names:
Source: Dickens, C. (1838). Oliver Twist.London, England; Bentley's Miscellany. http://etc.usf.edu/lit2go/50/oliver-twist/
Chapter 1: Treats of the Place Where Oliver Twist was Born and of the Circumstances Attending His Birth.
Chapter 2: Treats of Oliver Twist's Growth, Education, and Board.
Chapter 3: Relates How Oliver Twist was Very Near Getting a Place Which Would Not Have Been a Sinecure.
Chapter 11: Treats of Mr. Fang the Police Magistrate; And Furnishes a Slight Specimen of His Mode of Administering Justice.
Chapter 24: Treats on a Very Poor Subject. But is a Short One, and May be Found of Importance in this History.
Chapter 34: Contains Some Introductory Particulars Relative to a Young Gentleman Who Now Arrives Upon the Scene; And a New Adventure Which Happened to Oliver.
The examples I gave, and a few others, have chapter names that follow the pattern "Chapter XX does Y." Chapter 11, in particular has this structure twice.
So it looks like treats is being employed as a verb.
As for meaning? Treats can mean something like "provides." In modern English, it is usually used for desirable things and is usually followed by "to." (e.g. I treated the basketball team to ice cream after the game) I don't know if the convention wasn't established when Dickens wrote these chapter headings, or if he is just being colorful, but it looks like your quote means:
Chapter One describes the place where Oliver Twist was born.
Also, with acknowledgement to a comment by @Bob Jarvis: Dictionary.com's 9th definition for treat gives an example that uses treats + of: "to deal with a subject in speech or writing; discourse: (example) a work that treats of the caste system in India."
First, when you say:
German-American
it means your *ethnic" background is German (meaning your ancestors at some time were from Germany), but you were born in America. Or you were born in Germany but now permanantly residing in America.
This should apply to any nation specific usage.
As for:
African-American
this is more general. It could be like "European-American".
Such a person (or their ancestors) would be (or would be perceived to be) from that region of the world. I think we all know the general criteria used, but that is another discussion.
Best Answer
Generally speaking "hometown" tends to refer to the place you were born and raised in rather than where you currently live; however that may depend on where you are geographically at the time you say it!
To clarify what I mean by "born and raised" - it is entirely possible for someone to be born in one place but mainly raised in another - for example, if your parents lived in Liverpool at the time of your birth but your mother suddenly went into early labour whilst visiting London, you might end up being born in a London hospital with 'London' as the place of birth marked on your birth certificate (in the UK at least), yet you may never spend any of your childhood there. In those or similar circumstances, your "hometown" is where you were raised, and your place of birth is largely irrelevant to this.