Przekażemy darowiznę, byleby ubrania nie miały rozdarć.

Byleby means as long as, provided that, or so long as.

In this sentence, it introduces a condition:

Przekażemy darowiznę, byleby ubrania nie miały rozdarć.
= We’ll donate it / make the donation, as long as the clothes don’t have any tears.

It often carries the sense of this is the one important condition.

After words like byleby, żeby, and aby, Polish often uses a form that looks like the past tense, even when the meaning is present or future.

So nie miały here does not mean simple past didn’t have.
It means something more like:

• don’t have
• won’t have
• shouldn’t have

depending on context.

Polish does not have a separate subjunctive form like English sometimes does, so this past-looking form helps express a condition, wish, or requirement.

Because ubrania is plural here.

• singular: ubranie = a piece of clothing / a garment
• plural: ubrania = clothes / garments

Since ubrania is a non-masculine-personal plural noun, the verb must agree with it:

• ubrania miały = the clothes had / would have

So miały is the correct plural form.

Rozdarć is the genitive plural of rozdarcie (tear, rip).

Here that happens because Polish very often uses the genitive after negation:

• affirmative: mieć rozdarcia = to have tears/rips
• negative: nie mieć rozdarć = not to have tears/rips

This is a very common pattern in Polish. Compare:

• Mam czas. = I have time.
• Nie mam czasu. = I don’t have time.

So nie miały rozdarć is the standard structure.

It means we will make/pass on a donation.

• przekażemy = we will hand over / pass on / transfer
• darowiznę = donation (accusative singular of darowizna)

This sounds a bit more formal than just saying damy (we’ll give) or oddamy (we’ll give away).

So the sentence has a somewhat formal tone, especially because of darowizna.

Because it is the direct object of przekażemy.

The basic form is:

• darowizna = donation

But after a transitive verb like przekazać (to transfer / donate / hand over), a feminine noun usually goes into the accusative singular:

• darowizna → darowiznę

So:

• przekażemy darowiznę = we will donate / hand over a donation

Because byleby introduces a subordinate clause.

Polish normally puts a comma before conjunctions that introduce this kind of clause, such as:

• że
• żeby
• aby
• jeśli
• byleby

So the comma in:

Przekażemy darowiznę, byleby ubrania nie miały rozdarć.

is standard and required.

Yes, but the nuance changes a little.

• jeśli = if
• o ile = provided that / if
• byleby = as long as / provided that, often with the feeling that this is the main requirement

So:

• Przekażemy darowiznę, jeśli ubrania nie mają rozdarć.
  = more neutral, factual

• Przekażemy darowiznę, byleby ubrania nie miały rozdarć.
  = more like we’ll do it, as long as the clothes don’t have tears

So byleby sounds a bit more idiomatic and condition-focused.

They are related, but not identical.

• rozdarcie = tear / rip
  something has been torn
• dziura = hole
  an opening, not necessarily caused by tearing

So ubrania nie miały rozdarć specifically means the clothes should not have rips/tears.
If you wanted to say no holes, you would use dziur:

• żeby ubrania nie miały dziur = so that the clothes don’t have holes