Failed to find out the source of a certain portion of a link

I've created a script in python to scrape certain fields from a webpage. When I use this link in the script, it produces all the data in json format and I can parse it accordingly.

import requests

link = 'https://api-emis.kemenag.go.id/v1/institutions/pontren/public/identity/K1hOenRreVRmaWYwSGVzcERWVFpjZz09'

headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36'
}

with requests.Session() as s:
    s.headers.update(headers)
    res = s.get(link)
    container = res.json()['results']
    account_bank_holder = container['account_bank_holder']
    organizer_name = container['organizer_name']
    print((account_bank_holder,organizer_name))

However, the problem is that I can't figure out where this portion K1hOenRreVRmaWYwSGVzcERWVFpjZz09 at the end of the link is coming from.

This is how I found the link:

1. Navigate to this website
2. Select 2023/2024 Genap
3. Click the first item in the table: ACEH
4. Then, click the first item in the new table: ACEH SELATAN
5. Finally, click the first item in the new table: 500311010057

You should have the link by now, ending with the portion I mentioned above.

Question: Where is the portion similar to this K1hOenRreVRmaWYwSGVzcERWVFpjZz09 at the end of the final link coming from?

So, developer has used aes encryption along with base64 encoding.

import base64
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding

def aes_encrypt_cbc(plaintext: str) -> str:
    secret_key = b'a2c36eb2w1em50d6665dc5d61a68b400'
    base64_iv = "ZW1pc0Jhc2U2NElWa2V5cw=="
    iv = base64.b64decode(base64_iv)
    cipher = Cipher(algorithms.AES(secret_key), modes.CBC(iv), backend=default_backend())
    encryptor = cipher.encryptor()
    padder = padding.PKCS7(128).padder()
    padded_plaintext = padder.update(plaintext.encode()) + padder.finalize()
    ciphertext = encryptor.update(padded_plaintext) + encryptor.finalize()
    return base64.b64encode(base64.b64encode(ciphertext).decode().encode()).decode()

institution_id = "175974"
encrypted_text = aes_encrypt_cbc(institution_id)
print("Encrypted: ", encrypted_text)

Note: Initialization Vector and secret key may change in future.!