@Sakura please summarize this article, thanks uwu.
TLDR
Platåberget is a public, short-lived Ethereum testnet for trying out the upcoming Glamsterdam upgrade. Ethereum developers and operators are encouraged to test early—especially because gas changes may break existing apps and tools. 
Key Points
Glamsterdam introduces major consensus and execution-layer changes, including enshrined Proposer-Builder Separation (ePBS) and Block-Level Access Lists.
Gas repricing means tools that assume a fixed maximum gas limit—or that every ETH transfer costs exactly 21,000 gas—may need updates.
Contract and initcode size limits increase, and consensus data structures are updated for forward compatibility.
Anyone can join the testnet, run infrastructure, or submit validator and builder deposits.
The testnet is intended to catch problems before Glamsterdam reaches the longer-running Sepolia and Hoodi testnets, and eventually mainnet.
In-depth summary
Platåberget provides the community with a stable, public testing ground for Glamsterdam, rather than relying only on brief developer networks. Its validator set is open to public deposits, so solo stakers, infrastructure projects, and larger operators can test their validator and builder workflows. The article said the Glamsterdam fork was scheduled for August 20.
Glamsterdam includes changes across both Ethereum’s consensus and execution layers. ePBS changes how blocks are built, proposed, and validated; Block-Level Access Lists record state accessed and changed during blocks. The upgrade also raises maximum deployed contract size from 24 KiB to 64 KiB, and maximum initcode size from 48 KiB to 128 KiB.
The article particularly urges app and wallet developers to test the gas changes. Besides repricing operations, the upgrade adds a separate state-gas dimension for creating new state. For example, sending ETH to an account that already exists still costs 21,000 gas, but sending to a new account incurs an additional state-related charge. The article recommends using Platåberget to find and fix assumptions in wallets, indexers, gas estimators, and other tooling before the changes move to longer-lived testnets and, ultimately, mainnet.
ELI5
Platåberget is a practice version of Ethereum where people can try the next big update before it reaches the real network. Some of the rules are changing, especially how gas is counted, so developers should test their apps and fix anything that no longer works. 
Writers main point
Test Glamsterdam on Platåberget now—particularly gas-related changes—so infrastructure and applications can be fixed before the upgrade reaches Ethereum’s main network.