This reduces the number of lines of diff in PR 4166, which replaces the
entire `tracestate-probability-sampling.md` file with new contents.

Part of #4166.

## Changes

Move a file, place a link to it and explain that a change is in
progress.

### Context

- Add context propagation through Environment Variables specification.

([#4454](#4454))
- On Propagators API, stabilize `GetAll` on the `TextMap` Extract.

([#4472](#4472))

### Traces

- Define sampling threshold field in OpenTelemetry TraceState; define
the behavior
of TraceIdRatioBased sampler in terms of W3C Trace Context Level 2
randomness.

([#4166](#4166))

### Metrics

- Clarify SDK behavior for Instrument Advisory Parameter.

([#4389](#4389))

### Logs

- Add `Enabled` opt-in operation to the `LogRecordProcessor`.

([#4439](#4439))
- Stabilize `Logger.Enabled`.

([#4463](#4463))
- Stabilize `EventName`.

([#4475](#4475))

### Baggage

- Add context (baggage) propagation through Environment Variables
specification.

([#4454](#4454))

### Resource

- Add Datamodel for Entities.

([#4442](#4442))

### SDK Configuration

- Convert declarative config env var substitution syntax to ABNF.

([#4448](#4448))
- List declarative config supported SDK extension plugin interfaces.

([#4452](#4452))

---------

Co-authored-by: Armin Ruech <7052238+arminru@users.noreply.github.com>

July 2025 release.

### Context

- Add Supplementary Guidelines for environment variables as context
carrier
  specification.

([#4548](#4548))

### Traces

- Define sampling threshold field in OpenTelemetry TraceState; define
the behavior
of TraceIdRatioBased sampler in terms of W3C Trace Context Level 2
randomness.

([#4166](#4166))
- Define CompositeSampler implementation and built-in ComposableSampler
interfaces.

([#4466](#4466))
- Define how SDK implements `Tracer.Enabled`.

([#4537](#4537))

### Logs

- Stabilize `Event Name` parameter of `Logger.Enabled`.

([#4534](#4534))
- Stabilize SDK and No-Op `Logger.Enabled`.

([#4536](#4536))
- `SeverityNumber=0` MAY be used to represent an unspecified value.

([#4535](#4535))

### Baggage

- Add Supplementary Guidelines for environment variables as context
carrier
  specification.

([#4548](#4548))

### Compatibility

- Clarify expectations about Prometheus content negotiation for metric
names.

([#4543](#4543))

---------

Co-authored-by: Armin Ruech <7052238+arminru@users.noreply.github.com>
Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>

Part of #1413 
Fixes #4601 

## Changes

Restores TraceIdRatioBased specification from before
#4166.

* [x] Related issues #1413
* [x] Related [OTEP
235](https://github.com/open-telemetry/opentelemetry-specification/blob/main/oteps/trace/0235-sampling-threshold-in-trace-state.md)
* [x]
[`CHANGELOG.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CHANGELOG.md)
file updated for non-trivial changes

---------

Co-authored-by: Otmar Ertl <otmar.ertl@gmail.com>
Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>
Co-authored-by: Carlos Alberto Cortez <calberto.cortez@gmail.com>

Goal is to improve our public documentation, which has two documents
with the same title today, the second one being correct.

Finishes the deprecation process started in #4168.
When #4166 added the new sampling specification, the old one was
renamed.
Now that the new specification is complete in the specification, the old
one is a distraction.

## Changes

This moves the old document into the `oteps/` repository where it will
remain a permanent record of this effort.