### Context

- Align environment variable context propagation name restrictions with
POSIX.1-2024
  and define normalization behavior.

([open-telemetry#4944](open-telemetry#4944))
- Decouple the responsibilities of the environment variable propagation
carrier.

([open-telemetry#4961](open-telemetry#4961))
- Remove misleading implementation approach the environment variable
propagation.

([open-telemetry#5003](open-telemetry#5003))
- Change Environment Variables as Context Propagation Carriers document
status to Beta.

([open-telemetry#5020](open-telemetry#5020))

### Traces

- Stabilize Tracer `enabled` operation

([open-telemetry#4941](open-telemetry#4941))
- Stabilize `AlwaysRecord` sampler.

([open-telemetry#4934](open-telemetry#4934))

### Metrics

- Add development `maxExportBatchSize` parameter to Periodic exporting
MetricReader.

([open-telemetry#4895](open-telemetry#4895))

### Logs

- Add event to span event bridge.

([open-telemetry#5006](open-telemetry#5006))

### Resource

- Clarify that a Resource describes the observed entity, not the
component
  that technically emits telemetry.

([open-telemetry#4905](open-telemetry#4905))

### Compatibility

- Deprecate OpenTracing compatibility requirements in the specification.

([open-telemetry#4938](open-telemetry#4938))
- Stabilize sections of Prometheus and OpenMetrics Compatibility.
- Stabilize Prometheus Classic Histogram to OTLP Explicit Histogram
transformation.

([open-telemetry#4874](open-telemetry#4874))
  - Stabilize Prometheus Timestamp and Start timestamp transformation.

([open-telemetry#4953](open-telemetry#4953))
- Clarify Prometheus Native Histogram to OTLP Exponential Histogram
conversion,
add conversion rules for Native Histograms with Custom Buckets (NHCB) to
OTLP
    Histogram.

([open-telemetry#4898](open-telemetry#4898))
  - Stabilize Prometheus Dropped Types transformation.

([open-telemetry#4952](open-telemetry#4952))
- Stabilize OpenTelemetry Attributes to Prometheus labels
transformation.

([open-telemetry#4963](open-telemetry#4963))
- Stabilize Prometheus Exemplar to OpenTelemetry Exemplar
transformation.

([open-telemetry#4962](open-telemetry#4962))
  - Stabilize Prometheus Metadata transformation.

([open-telemetry#4954](open-telemetry#4954))
- Stabilize OpenTelemetry Metric Metadata to Prometheus metric metadata.

([open-telemetry#4966](open-telemetry#4966))
- Stabilize OpenTelemetry Exemplar to Prometheus Exemplar
transformation.

([open-telemetry#4964](open-telemetry#4964))
- Stabilize sections of Prometheus Metrics Exporter.
  - Stabilize host configuration.

([open-telemetry#5025](open-telemetry#5025))

### SDK Configuration

- Declarative configuration: add in-development guidance for exposing
the
  effective `Resource` returned by `Create`.

([open-telemetry#4949](open-telemetry#4949))
- Require spec changes to consider declarative config schema

([open-telemetry#4916](open-telemetry#4916))
- Add strict YAML parsing guidance to configuration supplementary
guidelines.

([open-telemetry#4878](open-telemetry#4878))

### OTEPs

- Process Context: Sharing Resource Attributes with External Readers.

([open-telemetry#4719](open-telemetry#4719))
- Support multiple Resources within an SDK.

([open-telemetry#4665](open-telemetry#4665))

---------

Co-authored-by: Jack Berg <34418638+jack-berg@users.noreply.github.com>

Fixes open-telemetry#4984

## Changes

Moves Prometheus Metrics Exporter spec **Host configuration** status
from `Development` to `Stable`. Implemented by [3+
SDKs](open-telemetry#4984 (comment)).

* [x] Related issues open-telemetry#4984
* [ ] Related [OTEP(s)](https://github.com/open-telemetry/oteps) #
* [ ] Links to the prototypes (when adding or changing features)
* [x]
[`CHANGELOG.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CHANGELOG.md)
file updated for non-trivial changes
* For trivial changes, include `[chore]` in the PR title to skip the
changelog check
* [ ] [Spec compliance
matrix](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix/template.yaml)
updated if necessary
* [ ] [Declarative config data
model](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/data-model.md#overview)
is updated if SDK config surface is changed

### Context

- Align environment variable context propagation name restrictions with
POSIX.1-2024
  and define normalization behavior.

([open-telemetry#4944](open-telemetry#4944))
- Decouple the responsibilities of the environment variable propagation
carrier.

([open-telemetry#4961](open-telemetry#4961))
- Remove misleading implementation approach the environment variable
propagation.

([open-telemetry#5003](open-telemetry#5003))
- Change Environment Variables as Context Propagation Carriers document
status to Beta.

([open-telemetry#5020](open-telemetry#5020))

### Traces

- Stabilize Tracer `enabled` operation

([open-telemetry#4941](open-telemetry#4941))
- Stabilize `AlwaysRecord` sampler.

([open-telemetry#4934](open-telemetry#4934))

### Metrics

- Add development `maxExportBatchSize` parameter to Periodic exporting
MetricReader.

([open-telemetry#4895](open-telemetry#4895))

### Logs

- Add event to span event bridge.

([open-telemetry#5006](open-telemetry#5006))

### Resource

- Clarify that a Resource describes the observed entity, not the
component
  that technically emits telemetry.

([open-telemetry#4905](open-telemetry#4905))

### Compatibility

- Deprecate OpenTracing compatibility requirements in the specification.

([open-telemetry#4938](open-telemetry#4938))
- Stabilize sections of Prometheus and OpenMetrics Compatibility.
- Stabilize Prometheus Classic Histogram to OTLP Explicit Histogram
transformation.

([open-telemetry#4874](open-telemetry#4874))
  - Stabilize Prometheus Timestamp and Start timestamp transformation.

([open-telemetry#4953](open-telemetry#4953))
- Clarify Prometheus Native Histogram to OTLP Exponential Histogram
conversion,
add conversion rules for Native Histograms with Custom Buckets (NHCB) to
OTLP
    Histogram.

([open-telemetry#4898](open-telemetry#4898))
  - Stabilize Prometheus Dropped Types transformation.

([open-telemetry#4952](open-telemetry#4952))
- Stabilize OpenTelemetry Attributes to Prometheus labels
transformation.

([open-telemetry#4963](open-telemetry#4963))
- Stabilize Prometheus Exemplar to OpenTelemetry Exemplar
transformation.

([open-telemetry#4962](open-telemetry#4962))
  - Stabilize Prometheus Metadata transformation.

([open-telemetry#4954](open-telemetry#4954))
- Stabilize OpenTelemetry Metric Metadata to Prometheus metric metadata.

([open-telemetry#4966](open-telemetry#4966))
- Stabilize OpenTelemetry Exemplar to Prometheus Exemplar
transformation.

([open-telemetry#4964](open-telemetry#4964))
- Stabilize sections of Prometheus Metrics Exporter.
  - Stabilize host configuration.

([open-telemetry#5025](open-telemetry#5025))

### SDK Configuration

- Declarative configuration: add in-development guidance for exposing
the
  effective `Resource` returned by `Create`.

([open-telemetry#4949](open-telemetry#4949))
- Require spec changes to consider declarative config schema

([open-telemetry#4916](open-telemetry#4916))
- Add strict YAML parsing guidance to configuration supplementary
guidelines.

([open-telemetry#4878](open-telemetry#4878))

### OTEPs

- Process Context: Sharing Resource Attributes with External Readers.

([open-telemetry#4719](open-telemetry#4719))
- Support multiple Resources within an SDK.

([open-telemetry#4665](open-telemetry#4665))

---------

Co-authored-by: Jack Berg <34418638+jack-berg@users.noreply.github.com>