What is the meaning/usage of に in the following sentence?

Question

ある事柄について感じた事(が、発表できる程度にまとまったもの)。

So, I understand the first sentence, but I'm a little confused about the second one.

My translation is: to have a feeling about a certain matter to the extent of being able to declare about it.

Answer 1

Isn't this an excerpt of a dictionary definition, like what this blog cites?

「感想」…ある事柄について感じた事（が、発表出来る程度にまとまったもの）。

In this case, it means:

what one thinks/feels about a certain matter (which has taken shape enough to be expressed/presented/published)

As you have correctly translated, 程度 means "(to) the extent/degree", or you could take Vできる程度 altogether as "enough to V". Anyway, both ～程度 and ～程度に stands for the adverbial phrase "to the degree", but the form with に is preferred when describing the state how the result is, while without に the manner how the action is done.

30cm程度切る cut (off) 30cm
30cm程度に切る cut into 30cm pieces or trim into 30cm long

Answer 2

The simple answer: the に in 発表できる程度にまとまったもの allows the adverb of degree 程度(extent) to modify まとまった.

発表できる程度 translates to "the extent it can be presented".

まとまる in this context translates to "to come together; to cohere".

In order to say that ある事柄について感じた事 has まとまった to 発表できる程度, we use に.

So:

ある事柄について感じた事(が、発表できる程度にまとまったもの)。

becomes, in English:

(The substance of) what you felt about a certain matter (that has become coherent enough to be able to be presented (outwardly)).

Answer 3

My understanding is that both parts of your sentence describe the もの mentioned at the very end of the sentence.

ある事柄について感じた事がまとまったもの

A thing that collects the things felt about a certain matter.

発表できる程度にまとまったもの

A thing that collects (something) to the degree of being able to present (it).